Fix BASE_URL config loading, add tasks/projects; robust .env path resolution

- Config: try ENV_FILE, .env, ../.env for loading; trim trailing slash from BaseURL
- Log BASE_URL at server startup for verification
- .env.example: document BASE_URL
- Tasks, projects, tags, migrations and related API/handlers

Made-with: Cursor

.env.example

@@ -11,8 +11,11 @@ JWT_SECRET=dev-secret-change-me
 SERVER_PORT=8080
 ENV=development
 
-# Base URL (used for public iCal feed URLs; defaults to http://localhost:$SERVER_PORT)
-# BASE_URL=https://api.example.com
+# Base URL for iCal feed URLs and availability URLs.
+# Defaults to http://localhost:$SERVER_PORT if unset.
+# Set to your public API URL for Google Calendar and external subscriptions.
+# Example: BASE_URL=https://api.example.com
+BASE_URL=http://localhost:8080
 
 # CORS (comma-separated origins; defaults to localhost:5173 for dev)
 # CORS_ORIGINS=https://app.example.com,https://www.example.com

cmd/server/main.go

@@ -25,6 +25,7 @@ import (
 
 func main() {
 	cfg := config.Load()
+	log.Printf("BASE_URL=%s", cfg.BaseURL)
 
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
@@ -86,19 +87,36 @@ func main() {
 	reminderSvc := service.NewReminderService(queries, calSvc, sched)
 	attendeeSvc := service.NewAttendeeService(queries, calSvc)
 
+	taskWebhookSvc := service.NewTaskWebhookService(queries)
+	taskSvc := service.NewTaskService(queries, auditSvc, taskWebhookSvc)
+	projectSvc := service.NewProjectService(queries, auditSvc)
+	tagSvc := service.NewTagService(queries)
+	taskDepSvc := service.NewTaskDependencyService(queries)
+	var taskReminderScheduler service.TaskReminderScheduler = scheduler.NoopScheduler{}
+	if realSched, ok := sched.(*scheduler.Scheduler); ok {
+		taskReminderScheduler = realSched
+	}
+	taskReminderSvc := service.NewTaskReminderService(queries, taskReminderScheduler)
+
 	h := api.Handlers{
-		Auth:         handlers.NewAuthHandler(authSvc, userSvc),
-		User:         handlers.NewUserHandler(userSvc),
-		Calendar:     handlers.NewCalendarHandler(calSvc),
-		Sharing:      handlers.NewSharingHandler(calSvc),
-		Event:        handlers.NewEventHandler(eventSvc),
-		Reminder:     handlers.NewReminderHandler(reminderSvc),
-		Attendee:     handlers.NewAttendeeHandler(attendeeSvc),
-		Contact:      handlers.NewContactHandler(contactSvc),
-		Availability: handlers.NewAvailabilityHandler(availSvc),
-		Booking:      handlers.NewBookingHandler(bookingSvc),
-		APIKey:       handlers.NewAPIKeyHandler(apiKeySvc),
-		ICS:          handlers.NewICSHandler(calSvc, eventSvc, queries),
+		Auth:           handlers.NewAuthHandler(authSvc, userSvc),
+		User:           handlers.NewUserHandler(userSvc),
+		Calendar:       handlers.NewCalendarHandler(calSvc),
+		Sharing:        handlers.NewSharingHandler(calSvc),
+		Event:          handlers.NewEventHandler(eventSvc),
+		Reminder:       handlers.NewReminderHandler(reminderSvc),
+		Attendee:       handlers.NewAttendeeHandler(attendeeSvc),
+		Contact:        handlers.NewContactHandler(contactSvc),
+		Availability:   handlers.NewAvailabilityHandler(availSvc),
+		Booking:        handlers.NewBookingHandler(bookingSvc),
+		APIKey:         handlers.NewAPIKeyHandler(apiKeySvc),
+		ICS:            handlers.NewICSHandler(calSvc, eventSvc, queries),
+		Task:           handlers.NewTaskHandler(taskSvc),
+		Project:        handlers.NewProjectHandler(projectSvc),
+		Tag:            handlers.NewTagHandler(tagSvc),
+		TaskDependency: handlers.NewTaskDependencyHandler(taskDepSvc),
+		TaskReminder:   handlers.NewTaskReminderHandler(taskReminderSvc),
+		TaskWebhook:    handlers.NewTaskWebhookHandler(taskWebhookSvc),
 	}
 
 	authMW := middleware.NewAuthMiddleware(jwtManager, queries)

frontend/dist/index.html

@@ -5,10 +5,10 @@
     <link rel="icon" type="image/svg+xml" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>📅</text></svg>" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>Calendar</title>
-    <script type="module" crossorigin src="/assets/index-DLhHVFKH.js"></script>
+    <script type="module" crossorigin src="/assets/index-DXAGcZdG.js"></script>
     <link rel="modulepreload" crossorigin href="/assets/vendor-BI0H_s0W.js">
     <link rel="modulepreload" crossorigin href="/assets/date-huy51PAD.js">
-    <link rel="stylesheet" crossorigin href="/assets/index-D1jwjSlk.css">
+    <link rel="stylesheet" crossorigin href="/assets/index-C8iK5eUL.css">
   </head>
   <body>
     <div id="root"></div>

frontend/src/App.tsx

@@ -4,6 +4,7 @@ import Login from "./pages/Login";
 import Register from "./pages/Register";
 import CalendarPage from "./pages/CalendarPage";
 import ContactsPage from "./pages/ContactsPage";
+import TodoPage from "./pages/TodoPage";
 import SettingsPage from "./pages/SettingsPage";
 
 function ProtectedRoute() {
@@ -53,6 +54,21 @@ function AppLayout() {
             <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M8 7V3m8 4V3m-9 8h10M5 21h14a2 2 0 002-2V7a2 2 0 00-2-2H5a2 2 0 00-2 2v12a2 2 0 002 2z" />
           </svg>
         </NavLink>
+        <NavLink
+          to="/todo"
+          className={({ isActive }) =>
+            `p-2.5 rounded-xl transition-colors ${
+              isActive
+                ? "bg-blue-100 dark:bg-blue-900/30 text-blue-600 dark:text-blue-400"
+                : "text-gray-500 dark:text-gray-400 hover:bg-gray-100 dark:hover:bg-gray-800 hover:text-gray-700 dark:hover:text-gray-300"
+            }`
+          }
+          title="To-do"
+        >
+          <svg className="w-5 h-5" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2m-6 9l2 2 4-4" />
+          </svg>
+        </NavLink>
         <NavLink
           to="/contacts"
           className={({ isActive }) =>
@@ -104,6 +120,7 @@ export default function App() {
       <Route element={<ProtectedRoute />}>
         <Route element={<AppLayout />}>
           <Route path="/" element={<CalendarPage />} />
+          <Route path="/todo" element={<TodoPage />} />
           <Route path="/contacts" element={<ContactsPage />} />
           <Route path="/settings" element={<SettingsPage />} />
         </Route>

frontend/src/api.ts

@@ -9,6 +9,9 @@ import type {
   Contact,
   ListResponse,
   PageInfo,
+  Project,
+  Tag,
+  Task,
   User,
 } from "./types";
 
@@ -295,4 +298,93 @@ export const api = {
 
   deleteContact: (id: string) =>
     request<{ ok: boolean }>(`/contacts/${id}`, { method: "DELETE" }),
+
+  // Tasks
+  listTasks: (params?: {
+    status?: string;
+    priority?: string;
+    project_id?: string;
+    due_from?: string;
+    due_to?: string;
+    limit?: number;
+    cursor?: string;
+  }) => {
+    const sp = new URLSearchParams({ limit: "100" });
+    if (params?.status) sp.set("status", params.status);
+    if (params?.priority) sp.set("priority", params.priority);
+    if (params?.project_id) sp.set("project_id", params.project_id);
+    if (params?.due_from) sp.set("due_from", params.due_from);
+    if (params?.due_to) sp.set("due_to", params.due_to);
+    if (params?.limit) sp.set("limit", String(params.limit));
+    if (params?.cursor) sp.set("cursor", params.cursor);
+    return request<ListResponse<Task>>(`/tasks?${sp}`);
+  },
+
+  createTask: (data: {
+    title: string;
+    description?: string;
+    status?: string;
+    priority?: string;
+    due_date?: string;
+    project_id?: string;
+    parent_id?: string;
+  }) =>
+    request<{ task: Task }>("/tasks", {
+      method: "POST",
+      body: JSON.stringify(data),
+    }),
+
+  getTask: (id: string) => request<{ task: Task }>(`/tasks/${id}`),
+
+  updateTask: (id: string, data: Partial<Task>) =>
+    request<{ task: Task }>(`/tasks/${id}`, {
+      method: "PUT",
+      body: JSON.stringify(data),
+    }),
+
+  deleteTask: (id: string, permanent?: boolean) => {
+    const q = permanent ? "?permanent=true" : "";
+    return request<{ ok: boolean }>(`/tasks/${id}${q}`, { method: "DELETE" });
+  },
+
+  markTaskComplete: (id: string) =>
+    request<{ task: Task }>(`/tasks/${id}/complete`, { method: "POST" }),
+
+  markTaskUncomplete: (id: string, status?: string) =>
+    request<{ task: Task }>(`/tasks/${id}/uncomplete`, {
+      method: "POST",
+      body: JSON.stringify(status ? { status } : {}),
+    }),
+
+  listTaskSubtasks: (id: string) =>
+    request<ListResponse<Task>>(`/tasks/${id}/subtasks`),
+
+  // Projects
+  listProjects: () => request<ListResponse<Project>>("/projects"),
+
+  createProject: (data: { name: string; color?: string }) =>
+    request<{ project: Project }>("/projects", {
+      method: "POST",
+      body: JSON.stringify(data),
+    }),
+
+  getProject: (id: string) => request<{ project: Project }>(`/projects/${id}`),
+
+  updateProject: (id: string, data: Partial<Project>) =>
+    request<{ project: Project }>(`/projects/${id}`, {
+      method: "PUT",
+      body: JSON.stringify(data),
+    }),
+
+  deleteProject: (id: string) =>
+    request<{ ok: boolean }>(`/projects/${id}`, { method: "DELETE" }),
+
+  // Tags
+  listTags: () => request<ListResponse<Tag>>("/tags"),
+
+  createTag: (data: { name: string; color?: string }) =>
+    request<{ tag: Tag }>("/tags", {
+      method: "POST",
+      body: JSON.stringify(data),
+    }),
 };

frontend/src/components/KanbanBoard.tsx

@@ -0,0 +1,100 @@
+import { useState } from "react";
+import type { Task } from "../types";
+import TaskCard from "./TaskCard";
+
+const KANBAN_COLUMNS = [
+  { id: "todo", title: "To Do", status: "todo" as const },
+  { id: "in_progress", title: "In Progress", status: "in_progress" as const },
+  { id: "done", title: "Done", status: "done" as const },
+];
+
+const ARCHIVED_COLUMN = { id: "archived", title: "Archived", status: "archived" as const };
+
+interface KanbanBoardProps {
+  tasks: Task[];
+  onTaskClick: (task: Task) => void;
+  onStatusChange: (taskId: string, newStatus: string) => void;
+  showArchived?: boolean;
+}
+
+export default function KanbanBoard({
+  tasks,
+  onTaskClick,
+  onStatusChange,
+  showArchived = false,
+}: KanbanBoardProps) {
+  const [draggedTask, setDraggedTask] = useState<Task | null>(null);
+  const [dragOverColumn, setDragOverColumn] = useState<string | null>(null);
+
+  const columns = showArchived ? [ARCHIVED_COLUMN] : KANBAN_COLUMNS;
+  const tasksByStatus = columns.reduce(
+    (acc, col) => {
+      acc[col.status] = tasks.filter((t) => t.status === col.status);
+      return acc;
+    },
+    {} as Record<string, Task[]>
+  );
+
+  const handleDragStart = (e: React.DragEvent, task: Task) => {
+    setDraggedTask(task);
+    e.dataTransfer.setData("text/plain", task.id);
+    e.dataTransfer.effectAllowed = "move";
+  };
+
+  const handleDragOver = (e: React.DragEvent, status: string) => {
+    e.preventDefault();
+    e.dataTransfer.dropEffect = "move";
+    setDragOverColumn(status);
+  };
+
+  const handleDragLeave = () => {
+    setDragOverColumn(null);
+  };
+
+  const handleDrop = (e: React.DragEvent, status: string) => {
+    e.preventDefault();
+    setDragOverColumn(null);
+    const taskId = e.dataTransfer.getData("text/plain");
+    if (taskId && draggedTask && draggedTask.status !== status) {
+      onStatusChange(taskId, status);
+    }
+    setDraggedTask(null);
+  };
+
+  return (
+    <div className="flex gap-4 overflow-x-auto pb-4 flex-1 min-h-0">
+      {columns.map((col) => (
+        <div
+          key={col.id}
+          onDragOver={(e) => handleDragOver(e, col.status)}
+          onDragLeave={handleDragLeave}
+          onDrop={(e) => handleDrop(e, col.status)}
+          className={`flex-shrink-0 w-72 flex flex-col rounded-lg border-2 transition-colors ${
+            dragOverColumn === col.status
+              ? "border-blue-400 dark:border-blue-500 bg-blue-50/50 dark:bg-blue-900/20"
+              : "border-gray-200 dark:border-gray-600"
+          }`}
+        >
+          <div className="p-3 border-b border-gray-200 dark:border-gray-600">
+            <h3 className="font-semibold text-gray-900 dark:text-gray-100">
+              {col.title}
+            </h3>
+            <p className="text-sm text-gray-500 dark:text-gray-400">
+              {tasksByStatus[col.status]?.length ?? 0} tasks
+            </p>
+          </div>
+          <div className="flex-1 p-3 overflow-y-auto space-y-2 min-h-[200px]">
+            {(tasksByStatus[col.status] ?? []).map((task) => (
+              <TaskCard
+                key={task.id}
+                task={task}
+                onDragStart={handleDragStart}
+                onClick={() => onTaskClick(task)}
+              />
+            ))}
+          </div>
+        </div>
+      ))}
+    </div>
+  );
+}

frontend/src/components/ProjectSidebar.tsx

@@ -0,0 +1,67 @@
+import type { Project } from "../types";
+
+interface ProjectSidebarProps {
+  projects: Project[];
+  selectedProjectId: string | null;
+  onSelectProject: (id: string | null) => void;
+  showArchived: boolean;
+  onToggleArchived: () => void;
+}
+
+export default function ProjectSidebar({
+  projects,
+  selectedProjectId,
+  onSelectProject,
+  showArchived,
+  onToggleArchived,
+}: ProjectSidebarProps) {
+  return (
+    <div className="w-56 flex-shrink-0 border-r border-gray-200 dark:border-gray-700 flex flex-col">
+      <div className="p-3 border-b border-gray-200 dark:border-gray-700">
+        <h3 className="font-semibold text-gray-900 dark:text-gray-100 text-sm">
+          Projects
+        </h3>
+      </div>
+      <div className="flex-1 overflow-y-auto p-2">
+        <button
+          onClick={() => onSelectProject(null)}
+          className={`w-full text-left px-3 py-2 rounded-lg text-sm transition-colors ${
+            selectedProjectId === null
+              ? "bg-blue-100 dark:bg-blue-900/30 text-blue-700 dark:text-blue-300"
+              : "text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700"
+          }`}
+        >
+          All Tasks
+        </button>
+        {projects.map((p) => (
+          <button
+            key={p.id}
+            onClick={() => onSelectProject(p.id)}
+            className={`w-full text-left px-3 py-2 rounded-lg text-sm transition-colors flex items-center gap-2 ${
+              selectedProjectId === p.id
+                ? "bg-blue-100 dark:bg-blue-900/30 text-blue-700 dark:text-blue-300"
+                : "text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700"
+            }`}
+          >
+            <span
+              className="w-3 h-3 rounded-full flex-shrink-0"
+              style={{ backgroundColor: p.color }}
+            />
+            {p.name}
+          </button>
+        ))}
+        <div className="mt-2 pt-2 border-t border-gray-200 dark:border-gray-700">
+          <label className="flex items-center gap-2 px-3 py-2 cursor-pointer text-sm text-gray-600 dark:text-gray-400">
+            <input
+              type="checkbox"
+              checked={showArchived}
+              onChange={onToggleArchived}
+              className="rounded border-gray-300 dark:border-gray-600"
+            />
+            Show archived
+          </label>
+        </div>
+      </div>
+    </div>
+  );
+}

frontend/src/components/TaskCard.tsx

@@ -0,0 +1,69 @@
+import type { Task } from "../types";
+import { format } from "date-fns";
+
+const priorityColors: Record<string, string> = {
+  low: "bg-gray-100 dark:bg-gray-700 text-gray-600 dark:text-gray-400",
+  medium: "bg-blue-100 dark:bg-blue-900/40 text-blue-700 dark:text-blue-300",
+  high: "bg-amber-100 dark:bg-amber-900/40 text-amber-700 dark:text-amber-300",
+  critical: "bg-red-100 dark:bg-red-900/40 text-red-700 dark:text-red-300",
+};
+
+interface TaskCardProps {
+  task: Task;
+  onDragStart?: (e: React.DragEvent, task: Task) => void;
+  onClick?: () => void;
+}
+
+export default function TaskCard({
+  task,
+  onDragStart,
+  onClick,
+}: TaskCardProps) {
+  const priorityClass = priorityColors[task.priority] || priorityColors.medium;
+
+  return (
+    <div
+      draggable={!!onDragStart}
+      onDragStart={(e) => onDragStart?.(e, task)}
+      onClick={onClick}
+      className="group cursor-pointer rounded-lg border border-gray-200 dark:border-gray-600 bg-white dark:bg-gray-800 p-3 shadow-sm hover:shadow-md transition-shadow"
+    >
+      <div className="flex items-start gap-2">
+        <div className="mt-0.5 cursor-grab active:cursor-grabbing text-gray-400 dark:text-gray-500 group-hover:text-gray-600 dark:group-hover:text-gray-400">
+          <svg className="w-4 h-4" fill="currentColor" viewBox="0 0 20 20">
+            <path d="M7 2a2 2 0 012 2v12a2 2 0 01-2 2h6a2 2 0 01-2-2V4a2 2 0 012-2h6z" />
+          </svg>
+        </div>
+        <div className="flex-1 min-w-0">
+          <p className="font-medium text-gray-900 dark:text-gray-100 truncate">
+            {task.title}
+          </p>
+          {task.due_date && (
+            <p className="text-xs text-gray-500 dark:text-gray-400 mt-1">
+              Due {format(new Date(task.due_date), "MMM d, yyyy")}
+            </p>
+          )}
+          <div className="flex flex-wrap gap-1 mt-2">
+            <span
+              className={`text-xs px-2 py-0.5 rounded ${priorityClass}`}
+            >
+              {task.priority}
+            </span>
+            {task.tags?.map((tag) => (
+              <span
+                key={tag.id}
+                className="text-xs px-2 py-0.5 rounded"
+                style={{
+                  backgroundColor: `${tag.color}20`,
+                  color: tag.color,
+                }}
+              >
+                {tag.name}
+              </span>
+            ))}
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+}

frontend/src/components/TaskModal.tsx

@@ -0,0 +1,271 @@
+import { useState, useEffect } from "react";
+import { format } from "date-fns";
+import type { Task, Project, Tag } from "../types";
+import { api } from "../api";
+import Modal from "./Modal";
+
+interface TaskModalProps {
+  open: boolean;
+  onClose: () => void;
+  onSaved: () => void;
+  task?: Task | null;
+  projects: Project[];
+  tags: Tag[];
+}
+
+const STATUS_OPTIONS = ["todo", "in_progress", "done"] as const;
+const PRIORITY_OPTIONS = ["low", "medium", "high", "critical"] as const;
+
+export default function TaskModal({
+  open,
+  onClose,
+  onSaved,
+  task,
+  projects,
+  tags,
+}: TaskModalProps) {
+  const isEdit = !!task;
+  const [title, setTitle] = useState("");
+  const [description, setDescription] = useState("");
+  const [status, setStatus] = useState<Task["status"]>("todo");
+  const [priority, setPriority] = useState<Task["priority"]>("medium");
+  const [dueDate, setDueDate] = useState("");
+  const [projectId, setProjectId] = useState("");
+  const [saving, setSaving] = useState(false);
+  const [error, setError] = useState("");
+  const [showDelete, setShowDelete] = useState(false);
+
+  useEffect(() => {
+    if (!open) return;
+    setError("");
+    setShowDelete(false);
+    if (task) {
+      setTitle(task.title);
+      setDescription(task.description || "");
+      setStatus(task.status);
+      setPriority(task.priority);
+      setDueDate(task.due_date ? format(new Date(task.due_date), "yyyy-MM-dd") : "");
+      setProjectId(task.project_id || "");
+    } else {
+      setTitle("");
+      setDescription("");
+      setStatus("todo");
+      setPriority("medium");
+      setDueDate("");
+      setProjectId("");
+    }
+  }, [open, task]);
+
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault();
+    if (!title.trim()) return;
+    setSaving(true);
+    setError("");
+    try {
+      if (isEdit) {
+        await api.updateTask(task!.id, {
+          title: title.trim(),
+          description: description || undefined,
+          status,
+          priority,
+          due_date: dueDate || undefined,
+          project_id: projectId || undefined,
+        });
+      } else {
+        await api.createTask({
+          title: title.trim(),
+          description: description || undefined,
+          status,
+          priority,
+          due_date: dueDate || undefined,
+          project_id: projectId || undefined,
+        });
+      }
+      onSaved();
+      onClose();
+    } catch (err: unknown) {
+      setError((err as { error?: string })?.error || "Failed to save task");
+    } finally {
+      setSaving(false);
+    }
+  };
+
+  const handleDelete = async () => {
+    if (!task) return;
+    setSaving(true);
+    try {
+      await api.deleteTask(task.id);
+      onSaved();
+      onClose();
+    } catch {
+      setError("Failed to delete task");
+    } finally {
+      setSaving(false);
+    }
+  };
+
+  return (
+    <Modal
+      open={open}
+      onClose={onClose}
+      title={isEdit ? "Edit Task" : "New Task"}
+      wide
+    >
+      <form onSubmit={handleSubmit} className="space-y-4">
+        {error && (
+          <div className="p-3 rounded-lg bg-red-50 dark:bg-red-900/20 text-red-600 dark:text-red-400 text-sm">
+            {error}
+          </div>
+        )}
+
+        <div>
+          <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
+            Title
+          </label>
+          <input
+            type="text"
+            value={title}
+            onChange={(e) => setTitle(e.target.value)}
+            className="w-full px-3 py-2 rounded-lg border border-gray-300 dark:border-gray-600 bg-white dark:bg-gray-700 text-gray-900 dark:text-gray-100"
+            placeholder="Task title"
+            required
+          />
+        </div>
+
+        <div>
+          <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
+            Description
+          </label>
+          <textarea
+            value={description}
+            onChange={(e) => setDescription(e.target.value)}
+            rows={3}
+            className="w-full px-3 py-2 rounded-lg border border-gray-300 dark:border-gray-600 bg-white dark:bg-gray-700 text-gray-900 dark:text-gray-100"
+            placeholder="Markdown supported"
+          />
+        </div>
+
+        <div className="grid grid-cols-2 gap-4">
+          <div>
+            <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
+              Status
+            </label>
+            <select
+              value={status}
+              onChange={(e) => setStatus(e.target.value as Task["status"])}
+              className="w-full px-3 py-2 rounded-lg border border-gray-300 dark:border-gray-600 bg-white dark:bg-gray-700 text-gray-900 dark:text-gray-100"
+            >
+              {STATUS_OPTIONS.map((s) => (
+                <option key={s} value={s}>
+                  {s.replace("_", " ")}
+                </option>
+              ))}
+            </select>
+          </div>
+          <div>
+            <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
+              Priority
+            </label>
+            <select
+              value={priority}
+              onChange={(e) => setPriority(e.target.value as Task["priority"])}
+              className="w-full px-3 py-2 rounded-lg border border-gray-300 dark:border-gray-600 bg-white dark:bg-gray-700 text-gray-900 dark:text-gray-100"
+            >
+              {PRIORITY_OPTIONS.map((p) => (
+                <option key={p} value={p}>
+                  {p}
+                </option>
+              ))}
+            </select>
+          </div>
+        </div>
+
+        <div className="grid grid-cols-2 gap-4">
+          <div>
+            <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
+              Due Date
+            </label>
+            <input
+              type="date"
+              value={dueDate}
+              onChange={(e) => setDueDate(e.target.value)}
+              className="w-full px-3 py-2 rounded-lg border border-gray-300 dark:border-gray-600 bg-white dark:bg-gray-700 text-gray-900 dark:text-gray-100"
+            />
+          </div>
+          <div>
+            <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
+              Project
+            </label>
+            <select
+              value={projectId}
+              onChange={(e) => setProjectId(e.target.value)}
+              className="w-full px-3 py-2 rounded-lg border border-gray-300 dark:border-gray-600 bg-white dark:bg-gray-700 text-gray-900 dark:text-gray-100"
+            >
+              <option value="">None</option>
+              {projects.map((p) => (
+                <option key={p.id} value={p.id}>
+                  {p.name}
+                </option>
+              ))}
+            </select>
+          </div>
+        </div>
+
+        <div className="flex justify-between pt-4">
+          <div>
+            {isEdit && (
+              <button
+                type="button"
+                onClick={() => setShowDelete(true)}
+                className="text-red-600 dark:text-red-400 hover:underline text-sm"
+              >
+                Delete task
+              </button>
+            )}
+          </div>
+          <div className="flex gap-2">
+            <button
+              type="button"
+              onClick={onClose}
+              className="px-4 py-2 rounded-lg border border-gray-300 dark:border-gray-600 text-gray-700 dark:text-gray-300 hover:bg-gray-50 dark:hover:bg-gray-700"
+            >
+              Cancel
+            </button>
+            <button
+              type="submit"
+              disabled={saving || !title.trim()}
+              className="px-4 py-2 rounded-lg bg-blue-600 text-white hover:bg-blue-700 disabled:opacity-50"
+            >
+              {saving ? "Saving..." : isEdit ? "Save" : "Create"}
+            </button>
+          </div>
+        </div>
+
+        {showDelete && (
+          <div className="mt-4 p-4 rounded-lg bg-red-50 dark:bg-red-900/20 border border-red-200 dark:border-red-800">
+            <p className="text-red-700 dark:text-red-300 text-sm mb-2">
+              Delete this task? This cannot be undone.
+            </p>
+            <div className="flex gap-2">
+              <button
+                type="button"
+                onClick={() => setShowDelete(false)}
+                className="px-3 py-1 rounded bg-gray-200 dark:bg-gray-600 text-sm"
+              >
+                Cancel
+              </button>
+              <button
+                type="button"
+                onClick={handleDelete}
+                disabled={saving}
+                className="px-3 py-1 rounded bg-red-600 text-white text-sm hover:bg-red-700 disabled:opacity-50"
+              >
+                Delete
+              </button>
+            </div>
+          </div>
+        )}
+      </form>
+    </Modal>
+  );
+}

frontend/src/pages/TodoPage.tsx

@@ -0,0 +1,137 @@
+import { useState, useEffect, useCallback } from "react";
+import type { Task, Project, Tag } from "../types";
+import { api } from "../api";
+import KanbanBoard from "../components/KanbanBoard";
+import TaskModal from "../components/TaskModal";
+import ProjectSidebar from "../components/ProjectSidebar";
+
+export default function TodoPage() {
+  const [tasks, setTasks] = useState<Task[]>([]);
+  const [projects, setProjects] = useState<Project[]>([]);
+  const [tags, setTags] = useState<Tag[]>([]);
+  const [loading, setLoading] = useState(true);
+  const [taskModalOpen, setTaskModalOpen] = useState(false);
+  const [selectedTask, setSelectedTask] = useState<Task | null>(null);
+  const [selectedProjectId, setSelectedProjectId] = useState<string | null>(null);
+  const [showArchived, setShowArchived] = useState(false);
+
+  const loadTasks = useCallback(async () => {
+    try {
+      const params: Parameters<typeof api.listTasks>[0] = {};
+      if (selectedProjectId) params.project_id = selectedProjectId;
+      const data = await api.listTasks(params);
+      setTasks((data.items || []) as Task[]);
+    } catch {
+      setTasks([]);
+    }
+  }, [selectedProjectId]);
+
+  const loadProjects = useCallback(async () => {
+    try {
+      const data = await api.listProjects();
+      setProjects(data.items || []);
+    } catch {
+      setProjects([]);
+    }
+  }, []);
+
+  const loadTags = useCallback(async () => {
+    try {
+      const data = await api.listTags();
+      setTags(data.items || []);
+    } catch {
+      setTags([]);
+    }
+  }, []);
+
+  useEffect(() => {
+    setLoading(true);
+    Promise.all([loadTasks(), loadProjects(), loadTags()]).finally(() =>
+      setLoading(false)
+    );
+  }, [loadTasks, loadProjects, loadTags]);
+
+  const handleTaskClick = (task: Task) => {
+    setSelectedTask(task);
+    setTaskModalOpen(true);
+  };
+
+  const handleStatusChange = async (taskId: string, newStatus: string) => {
+    try {
+      if (newStatus === "done") {
+        await api.markTaskComplete(taskId);
+      } else {
+        await api.markTaskUncomplete(taskId, newStatus);
+      }
+      loadTasks();
+    } catch {
+      setTasks((prev) => prev);
+    }
+  };
+
+  const handleSaved = () => {
+    loadTasks();
+  };
+
+  const handleCloseModal = () => {
+    setTaskModalOpen(false);
+    setSelectedTask(null);
+  };
+
+  const displayTasks = showArchived
+    ? tasks.filter((t) => t.status === "archived")
+    : tasks.filter((t) => t.status !== "archived");
+
+  return (
+    <div className="h-full flex flex-col bg-gray-50 dark:bg-gray-900">
+      <div className="flex items-center justify-between px-6 py-4 border-b border-gray-200 dark:border-gray-700">
+        <h1 className="text-xl font-semibold text-gray-900 dark:text-gray-100">
+          To-do List
+        </h1>
+        <button
+          onClick={() => {
+            setSelectedTask(null);
+            setTaskModalOpen(true);
+          }}
+          className="px-4 py-2 rounded-lg bg-blue-600 text-white hover:bg-blue-700 transition-colors"
+        >
+          New Task
+        </button>
+      </div>
+
+      <div className="flex-1 flex overflow-hidden">
+        <ProjectSidebar
+          projects={projects}
+          selectedProjectId={selectedProjectId}
+          onSelectProject={setSelectedProjectId}
+          showArchived={showArchived}
+          onToggleArchived={() => setShowArchived((s) => !s)}
+        />
+
+        <div className="flex-1 overflow-hidden p-4">
+          {loading ? (
+            <div className="flex items-center justify-center h-64">
+              <div className="w-8 h-8 border-2 border-blue-600 border-t-transparent rounded-full animate-spin" />
+            </div>
+          ) : (
+            <KanbanBoard
+              tasks={displayTasks}
+              onTaskClick={handleTaskClick}
+              onStatusChange={handleStatusChange}
+              showArchived={showArchived}
+            />
+          )}
+        </div>
+      </div>
+
+      <TaskModal
+        open={taskModalOpen}
+        onClose={handleCloseModal}
+        onSaved={handleSaved}
+        task={selectedTask}
+        projects={projects}
+        tags={tags}
+      />
+    </div>
+  );
+}

frontend/src/types.ts

@@ -137,6 +137,48 @@ export type APIKeyScopes = {
   calendars?: ("read" | "write")[];
   events?: ("read" | "write")[];
   contacts?: ("read" | "write")[];
+  tasks?: ("read" | "write")[];
   availability?: ("read")[];
   booking?: ("write")[];
 };
+
+export type TaskStatus = "todo" | "in_progress" | "done" | "archived";
+export type TaskPriority = "low" | "medium" | "high" | "critical";
+
+export interface Task {
+  id: string;
+  title: string;
+  description?: string;
+  status: TaskStatus;
+  priority: TaskPriority;
+  due_date?: string;
+  completed_at?: string;
+  created_at: string;
+  updated_at: string;
+  owner_id: string;
+  project_id?: string;
+  parent_id?: string;
+  subtasks?: Task[];
+  tags?: Tag[];
+  completion_percentage?: number;
+}
+
+export interface Project {
+  id: string;
+  owner_id: string;
+  name: string;
+  color: string;
+  is_shared: boolean;
+  deadline?: string;
+  sort_order?: number;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface Tag {
+  id: string;
+  owner_id: string;
+  name: string;
+  color: string;
+  created_at: string;
+}

frontend/tsconfig.tsbuildinfo

@@ -1 +1 @@
-{"root":["./src/App.tsx","./src/api.ts","./src/main.tsx","./src/types.ts","./src/vite-env.d.ts","./src/components/AddCalendarUrlModal.tsx","./src/components/CalendarModal.tsx","./src/components/DayView.tsx","./src/components/ErrorBoundary.tsx","./src/components/EventModal.tsx","./src/components/MiniCalendar.tsx","./src/components/Modal.tsx","./src/components/MonthView.tsx","./src/components/WeekView.tsx","./src/context/AuthContext.tsx","./src/context/ThemeContext.tsx","./src/pages/CalendarPage.tsx","./src/pages/ContactsPage.tsx","./src/pages/Login.tsx","./src/pages/Register.tsx","./src/pages/SettingsPage.tsx"],"version":"5.7.3"}
+{"root":["./src/App.tsx","./src/api.ts","./src/main.tsx","./src/types.ts","./src/vite-env.d.ts","./src/components/AddCalendarUrlModal.tsx","./src/components/CalendarModal.tsx","./src/components/DayView.tsx","./src/components/ErrorBoundary.tsx","./src/components/EventModal.tsx","./src/components/KanbanBoard.tsx","./src/components/MiniCalendar.tsx","./src/components/Modal.tsx","./src/components/MonthView.tsx","./src/components/ProjectSidebar.tsx","./src/components/TaskCard.tsx","./src/components/TaskModal.tsx","./src/components/WeekView.tsx","./src/context/AuthContext.tsx","./src/context/ThemeContext.tsx","./src/pages/CalendarPage.tsx","./src/pages/ContactsPage.tsx","./src/pages/Login.tsx","./src/pages/Register.tsx","./src/pages/SettingsPage.tsx","./src/pages/TodoPage.tsx"],"version":"5.7.3"}

internal/api/handlers/project.go

@@ -0,0 +1,185 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/calendarapi/internal/middleware"
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/service"
+	"github.com/calendarapi/internal/utils"
+	"github.com/go-chi/chi/v5"
+)
+
+type ProjectHandler struct {
+	projectSvc *service.ProjectService
+}
+
+func NewProjectHandler(projectSvc *service.ProjectService) *ProjectHandler {
+	return &ProjectHandler{projectSvc: projectSvc}
+}
+
+func (h *ProjectHandler) List(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+
+	projects, err := h.projectSvc.List(r.Context(), userID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteList(w, projects, models.PageInfo{Limit: len(projects)})
+}
+
+func (h *ProjectHandler) Create(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+
+	var req struct {
+		Name     string  `json:"name"`
+		Color    *string `json:"color"`
+		IsShared *bool   `json:"is_shared"`
+		Deadline *string `json:"deadline"`
+		SortOrder *int   `json:"sort_order"`
+	}
+	if err := utils.DecodeJSON(r, &req); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	createReq := service.CreateProjectRequest{
+		Name:     req.Name,
+		Color:    req.Color,
+		IsShared: req.IsShared,
+		SortOrder: req.SortOrder,
+	}
+	if req.Deadline != nil {
+		if t, err := utils.ParseTime(*req.Deadline); err == nil {
+			createReq.Deadline = &t
+		}
+	}
+
+	project, err := h.projectSvc.Create(r.Context(), userID, createReq)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"project": project})
+}
+
+func (h *ProjectHandler) Get(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	projectID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	project, err := h.projectSvc.Get(r.Context(), userID, projectID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"project": project})
+}
+
+func (h *ProjectHandler) Update(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	projectID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	var req struct {
+		Name     *string `json:"name"`
+		Color    *string `json:"color"`
+		IsShared *bool   `json:"is_shared"`
+		Deadline *string `json:"deadline"`
+		SortOrder *int   `json:"sort_order"`
+	}
+	if err := utils.DecodeJSON(r, &req); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	updateReq := service.UpdateProjectRequest{
+		Name:     req.Name,
+		Color:    req.Color,
+		IsShared: req.IsShared,
+		SortOrder: req.SortOrder,
+	}
+	if req.Deadline != nil {
+		if t, err := utils.ParseTime(*req.Deadline); err == nil {
+			updateReq.Deadline = &t
+		}
+	}
+
+	project, err := h.projectSvc.Update(r.Context(), userID, projectID, updateReq)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"project": project})
+}
+
+func (h *ProjectHandler) Delete(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	projectID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	if err := h.projectSvc.Delete(r.Context(), userID, projectID); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteOK(w)
+}
+
+func (h *ProjectHandler) Share(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	projectID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	var req struct {
+		Target struct {
+			Email string `json:"email"`
+		} `json:"target"`
+		Role string `json:"role"`
+	}
+	if err := utils.DecodeJSON(r, &req); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	if err := h.projectSvc.Share(r.Context(), userID, projectID, req.Target.Email, req.Role); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteOK(w)
+}
+
+func (h *ProjectHandler) ListMembers(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	projectID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	members, err := h.projectSvc.ListMembers(r.Context(), userID, projectID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"members": members})
+}

internal/api/handlers/tag.go

@@ -0,0 +1,159 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/calendarapi/internal/middleware"
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/service"
+	"github.com/calendarapi/internal/utils"
+	"github.com/go-chi/chi/v5"
+)
+
+type TagHandler struct {
+	tagSvc *service.TagService
+}
+
+func NewTagHandler(tagSvc *service.TagService) *TagHandler {
+	return &TagHandler{tagSvc: tagSvc}
+}
+
+func (h *TagHandler) List(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+
+	tags, err := h.tagSvc.List(r.Context(), userID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteList(w, tags, models.PageInfo{Limit: len(tags)})
+}
+
+func (h *TagHandler) Create(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+
+	var req struct {
+		Name  string  `json:"name"`
+		Color *string `json:"color"`
+	}
+	if err := utils.DecodeJSON(r, &req); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	tag, err := h.tagSvc.Create(r.Context(), userID, service.CreateTagRequest{
+		Name:  req.Name,
+		Color: req.Color,
+	})
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"tag": tag})
+}
+
+func (h *TagHandler) Get(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	tagID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	tag, err := h.tagSvc.Get(r.Context(), userID, tagID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"tag": tag})
+}
+
+func (h *TagHandler) Update(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	tagID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	var req struct {
+		Name  *string `json:"name"`
+		Color *string `json:"color"`
+	}
+	if err := utils.DecodeJSON(r, &req); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	tag, err := h.tagSvc.Update(r.Context(), userID, tagID, service.UpdateTagRequest{
+		Name:  req.Name,
+		Color: req.Color,
+	})
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"tag": tag})
+}
+
+func (h *TagHandler) Delete(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	tagID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	if err := h.tagSvc.Delete(r.Context(), userID, tagID); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteOK(w)
+}
+
+func (h *TagHandler) AttachToTask(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	tagID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "taskId"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	if err := h.tagSvc.AttachToTask(r.Context(), userID, tagID, taskID); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteOK(w)
+}
+
+func (h *TagHandler) DetachFromTask(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	tagID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "taskId"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	if err := h.tagSvc.DetachFromTask(r.Context(), userID, tagID, taskID); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteOK(w)
+}

internal/api/handlers/task.go

@@ -0,0 +1,263 @@
+package handlers
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/calendarapi/internal/middleware"
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/service"
+	"github.com/calendarapi/internal/utils"
+	"github.com/go-chi/chi/v5"
+)
+
+type TaskHandler struct {
+	taskSvc *service.TaskService
+}
+
+func NewTaskHandler(taskSvc *service.TaskService) *TaskHandler {
+	return &TaskHandler{taskSvc: taskSvc}
+}
+
+func (h *TaskHandler) List(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	q := r.URL.Query()
+
+	params := service.ListTasksParams{
+		Limit: 50,
+	}
+	if s := q.Get("status"); s != "" {
+		params.Status = &s
+	}
+	if p := q.Get("priority"); p != "" {
+		params.Priority = &p
+	}
+	if pid := q.Get("project_id"); pid != "" {
+		if id, err := utils.ValidateUUID(pid); err == nil {
+			params.ProjectID = &id
+		}
+	}
+	if df := q.Get("due_from"); df != "" {
+		if t, err := utils.ParseTime(df); err == nil {
+			params.DueFrom = &t
+		}
+	}
+	if dt := q.Get("due_to"); dt != "" {
+		if t, err := utils.ParseTime(dt); err == nil {
+			params.DueTo = &t
+		}
+	}
+	if l := q.Get("limit"); l != "" {
+		if v, err := strconv.Atoi(l); err == nil {
+			params.Limit = v
+		}
+	}
+	params.Cursor = q.Get("cursor")
+
+	tasks, cursor, err := h.taskSvc.List(r.Context(), userID, params)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	limit := int(utils.ClampLimit(params.Limit))
+	page := models.PageInfo{Limit: limit}
+	if cursor != nil {
+		page.NextCursor = cursor
+	}
+	utils.WriteList(w, tasks, page)
+}
+
+func (h *TaskHandler) Create(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+
+	var req struct {
+		Title          string  `json:"title"`
+		Description    *string `json:"description"`
+		Status         *string `json:"status"`
+		Priority       *string `json:"priority"`
+		DueDate        *string `json:"due_date"`
+		ProjectID      *string `json:"project_id"`
+		ParentID       *string `json:"parent_id"`
+		SortOrder      *int    `json:"sort_order"`
+		RecurrenceRule *string `json:"recurrence_rule"`
+	}
+	if err := utils.DecodeJSON(r, &req); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	createReq := service.CreateTaskRequest{
+		Title:          req.Title,
+		Description:    req.Description,
+		Status:         req.Status,
+		Priority:       req.Priority,
+		SortOrder:      req.SortOrder,
+		RecurrenceRule: req.RecurrenceRule,
+	}
+	if req.DueDate != nil {
+		if t, err := utils.ParseTime(*req.DueDate); err == nil {
+			createReq.DueDate = &t
+		}
+	}
+	if req.ProjectID != nil {
+		if id, err := utils.ValidateUUID(*req.ProjectID); err == nil {
+			createReq.ProjectID = &id
+		}
+	}
+	if req.ParentID != nil {
+		if id, err := utils.ValidateUUID(*req.ParentID); err == nil {
+			createReq.ParentID = &id
+		}
+	}
+
+	task, err := h.taskSvc.Create(r.Context(), userID, createReq)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"task": task})
+}
+
+func (h *TaskHandler) Get(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	task, err := h.taskSvc.Get(r.Context(), userID, taskID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"task": task})
+}
+
+func (h *TaskHandler) Update(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	var req struct {
+		Title          *string `json:"title"`
+		Description    *string `json:"description"`
+		Status         *string `json:"status"`
+		Priority       *string `json:"priority"`
+		DueDate        *string `json:"due_date"`
+		ProjectID      *string `json:"project_id"`
+		SortOrder      *int    `json:"sort_order"`
+		RecurrenceRule *string `json:"recurrence_rule"`
+	}
+	if err := utils.DecodeJSON(r, &req); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	updateReq := service.UpdateTaskRequest{
+		Title:          req.Title,
+		Description:    req.Description,
+		Status:         req.Status,
+		Priority:       req.Priority,
+		SortOrder:      req.SortOrder,
+		RecurrenceRule: req.RecurrenceRule,
+	}
+	if req.DueDate != nil {
+		if t, err := utils.ParseTime(*req.DueDate); err == nil {
+			updateReq.DueDate = &t
+		}
+	}
+	if req.ProjectID != nil {
+		if id, err := utils.ValidateUUID(*req.ProjectID); err == nil {
+			updateReq.ProjectID = &id
+		}
+	}
+
+	task, err := h.taskSvc.Update(r.Context(), userID, taskID, updateReq)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"task": task})
+}
+
+func (h *TaskHandler) Delete(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	permanent := r.URL.Query().Get("permanent") == "true"
+
+	if err := h.taskSvc.Delete(r.Context(), userID, taskID, permanent); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteOK(w)
+}
+
+func (h *TaskHandler) MarkComplete(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	task, err := h.taskSvc.MarkComplete(r.Context(), userID, taskID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"task": task})
+}
+
+func (h *TaskHandler) MarkUncomplete(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	var req struct {
+		Status *string `json:"status"`
+	}
+	_ = utils.DecodeJSON(r, &req)
+
+	task, err := h.taskSvc.MarkUncomplete(r.Context(), userID, taskID, req.Status)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"task": task})
+}
+
+func (h *TaskHandler) ListSubtasks(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	tasks, err := h.taskSvc.ListSubtasks(r.Context(), userID, taskID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteList(w, tasks, models.PageInfo{Limit: len(tasks)})
+}

internal/api/handlers/task_dependency.go

@@ -0,0 +1,88 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/calendarapi/internal/middleware"
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/service"
+	"github.com/calendarapi/internal/utils"
+	"github.com/go-chi/chi/v5"
+)
+
+type TaskDependencyHandler struct {
+	depSvc *service.TaskDependencyService
+}
+
+func NewTaskDependencyHandler(depSvc *service.TaskDependencyService) *TaskDependencyHandler {
+	return &TaskDependencyHandler{depSvc: depSvc}
+}
+
+func (h *TaskDependencyHandler) ListBlockers(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	tasks, err := h.depSvc.ListBlockers(r.Context(), userID, taskID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteList(w, tasks, models.PageInfo{Limit: len(tasks)})
+}
+
+func (h *TaskDependencyHandler) Add(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	var req struct {
+		BlocksTaskID string `json:"blocks_task_id"`
+	}
+	if err := utils.DecodeJSON(r, &req); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	blocksTaskID, err := utils.ValidateUUID(req.BlocksTaskID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	if err := h.depSvc.Add(r.Context(), userID, taskID, blocksTaskID); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteOK(w)
+}
+
+func (h *TaskDependencyHandler) Remove(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	blocksTaskID, err := utils.ValidateUUID(chi.URLParam(r, "blocksTaskId"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	if err := h.depSvc.Remove(r.Context(), userID, taskID, blocksTaskID); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteOK(w)
+}

internal/api/handlers/task_reminder.go

@@ -0,0 +1,94 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/calendarapi/internal/middleware"
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/service"
+	"github.com/calendarapi/internal/utils"
+	"github.com/go-chi/chi/v5"
+)
+
+type TaskReminderHandler struct {
+	reminderSvc *service.TaskReminderService
+}
+
+func NewTaskReminderHandler(reminderSvc *service.TaskReminderService) *TaskReminderHandler {
+	return &TaskReminderHandler{reminderSvc: reminderSvc}
+}
+
+func (h *TaskReminderHandler) List(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	reminders, err := h.reminderSvc.List(r.Context(), userID, taskID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteList(w, reminders, models.PageInfo{Limit: len(reminders)})
+}
+
+func (h *TaskReminderHandler) Add(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	var req struct {
+		Type        string                 `json:"type"`
+		Config      map[string]interface{} `json:"config"`
+		ScheduledAt string                 `json:"scheduled_at"`
+	}
+	if err := utils.DecodeJSON(r, &req); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	t, err := utils.ParseTime(req.ScheduledAt)
+	if err != nil {
+		utils.WriteError(w, models.NewValidationError("invalid scheduled_at"))
+		return
+	}
+
+	reminder, err := h.reminderSvc.Create(r.Context(), userID, taskID, service.CreateTaskReminderRequest{
+		Type:        req.Type,
+		Config:      req.Config,
+		ScheduledAt: t,
+	})
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"reminder": reminder})
+}
+
+func (h *TaskReminderHandler) Delete(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	taskID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+	reminderID, err := utils.ValidateUUID(chi.URLParam(r, "reminderId"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	if err := h.reminderSvc.Delete(r.Context(), userID, taskID, reminderID); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteOK(w)
+}

internal/api/handlers/task_webhook.go

@@ -0,0 +1,73 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/calendarapi/internal/middleware"
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/service"
+	"github.com/calendarapi/internal/utils"
+	"github.com/go-chi/chi/v5"
+)
+
+type TaskWebhookHandler struct {
+	webhookSvc *service.TaskWebhookService
+}
+
+func NewTaskWebhookHandler(webhookSvc *service.TaskWebhookService) *TaskWebhookHandler {
+	return &TaskWebhookHandler{webhookSvc: webhookSvc}
+}
+
+func (h *TaskWebhookHandler) List(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+
+	webhooks, err := h.webhookSvc.List(r.Context(), userID)
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteList(w, webhooks, models.PageInfo{Limit: len(webhooks)})
+}
+
+func (h *TaskWebhookHandler) Create(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+
+	var req struct {
+		URL    string   `json:"url"`
+		Events []string `json:"events"`
+		Secret *string  `json:"secret"`
+	}
+	if err := utils.DecodeJSON(r, &req); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	webhook, err := h.webhookSvc.Create(r.Context(), userID, service.TaskWebhookCreateRequest{
+		URL:    req.URL,
+		Events: req.Events,
+		Secret: req.Secret,
+	})
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteJSON(w, http.StatusOK, map[string]interface{}{"webhook": webhook})
+}
+
+func (h *TaskWebhookHandler) Delete(w http.ResponseWriter, r *http.Request) {
+	userID, _ := middleware.GetUserID(r.Context())
+	webhookID, err := utils.ValidateUUID(chi.URLParam(r, "id"))
+	if err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	if err := h.webhookSvc.Delete(r.Context(), userID, webhookID); err != nil {
+		utils.WriteError(w, err)
+		return
+	}
+
+	utils.WriteOK(w)
+}

internal/api/openapi/specs/base.json

@@ -33,7 +33,11 @@
     { "name": "Availability", "description": "Calendar availability queries" },
     { "name": "Booking", "description": "Public booking links and reservations" },
     { "name": "ICS", "description": "ICS calendar import and export" },
-    { "name": "Subscriptions", "description": "Calendar subscriptions (external iCal feeds)" }
+    { "name": "Subscriptions", "description": "Calendar subscriptions (external iCal feeds)" },
+    { "name": "Tasks", "description": "Task and to-do management" },
+    { "name": "Projects", "description": "Project/list grouping for tasks" },
+    { "name": "Tags", "description": "Tag management for tasks" },
+    { "name": "Webhooks", "description": "Task webhook configuration" }
   ],
   "security": [
     { "BearerAuth": [] },

internal/api/openapi/specs/projects.json

@@ -0,0 +1,229 @@
+{
+  "paths": {
+    "/projects": {
+      "get": {
+        "tags": ["Projects"],
+        "summary": "List projects",
+        "description": "Returns the authenticated user's projects (owned and shared). Requires `tasks:read` scope.",
+        "operationId": "listProjects",
+        "parameters": [
+          { "name": "limit", "in": "query", "schema": { "type": "integer", "minimum": 1, "maximum": 200, "default": 50 } },
+          { "name": "cursor", "in": "query", "schema": { "type": "string" }, "description": "Pagination cursor" }
+        ],
+        "responses": {
+          "200": {
+            "description": "List of projects",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["items", "page"],
+                  "properties": {
+                    "items": { "type": "array", "items": { "$ref": "#/components/schemas/Project" } },
+                    "page": { "$ref": "#/components/schemas/PageInfo" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "post": {
+        "tags": ["Projects"],
+        "summary": "Create a project",
+        "description": "Creates a new project for the authenticated user. Requires `tasks:write` scope.",
+        "operationId": "createProject",
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "required": ["name"],
+                "properties": {
+                  "name": { "type": "string", "minLength": 1, "maxLength": 100 },
+                  "color": { "type": "string", "pattern": "^#[0-9A-Fa-f]{6}$", "example": "#3B82F6" },
+                  "deadline": { "type": "string", "format": "date-time" },
+                  "sort_order": { "type": "integer" }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Project created",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["project"],
+                  "properties": {
+                    "project": { "$ref": "#/components/schemas/Project" }
+                  }
+                }
+              }
+            }
+          },
+          "400": { "description": "Validation error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/projects/{id}": {
+      "get": {
+        "tags": ["Projects"],
+        "summary": "Get a project",
+        "description": "Returns a single project by ID. User must be owner or member. Requires `tasks:read` scope.",
+        "operationId": "getProject",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": {
+            "description": "Project details",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["project"],
+                  "properties": {
+                    "project": { "$ref": "#/components/schemas/Project" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Project not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "put": {
+        "tags": ["Projects"],
+        "summary": "Update a project",
+        "description": "Updates a project. Requires `tasks:write` scope and owner/editor role.",
+        "operationId": "updateProject",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "properties": {
+                  "name": { "type": "string", "minLength": 1, "maxLength": 100 },
+                  "color": { "type": "string", "pattern": "^#[0-9A-Fa-f]{6}$" },
+                  "deadline": { "type": "string", "format": "date-time", "nullable": true },
+                  "sort_order": { "type": "integer" }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Project updated",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["project"],
+                  "properties": {
+                    "project": { "$ref": "#/components/schemas/Project" }
+                  }
+                }
+              }
+            }
+          },
+          "400": { "description": "Validation error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Project not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "delete": {
+        "tags": ["Projects"],
+        "summary": "Delete a project",
+        "description": "Deletes a project. Requires `tasks:write` scope and owner role.",
+        "operationId": "deleteProject",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": { "description": "Project deleted", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OkResponse" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Project not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/projects/{id}/share": {
+      "post": {
+        "tags": ["Projects"],
+        "summary": "Share project",
+        "description": "Shares a project with a user by email. Requires `tasks:write` scope and owner/editor role.",
+        "operationId": "shareProject",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "required": ["email", "role"],
+                "properties": {
+                  "email": { "type": "string", "format": "email" },
+                  "role": { "type": "string", "enum": ["editor", "viewer"] }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": { "description": "Project shared", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OkResponse" } } } },
+          "400": { "description": "Validation error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Project not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/projects/{id}/members": {
+      "get": {
+        "tags": ["Projects"],
+        "summary": "List project members",
+        "description": "Returns members of a project. Requires `tasks:read` scope.",
+        "operationId": "listProjectMembers",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": {
+            "description": "List of project members",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["items"],
+                  "properties": {
+                    "items": { "type": "array", "items": { "$ref": "#/components/schemas/ProjectMember" } }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Project not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    }
+  }
+}

internal/api/openapi/specs/schemas.json

@@ -188,6 +188,86 @@
           "start": { "type": "string", "format": "date-time" },
           "end": { "type": "string", "format": "date-time" }
         }
+      },
+      "Task": {
+        "type": "object",
+        "required": ["id", "title", "status", "priority", "owner_id", "created_at", "updated_at"],
+        "properties": {
+          "id": { "type": "string", "format": "uuid" },
+          "title": { "type": "string", "minLength": 1, "maxLength": 500 },
+          "description": { "type": "string", "nullable": true, "description": "Markdown supported" },
+          "status": { "type": "string", "enum": ["todo", "in_progress", "done", "archived"] },
+          "priority": { "type": "string", "enum": ["low", "medium", "high", "critical"] },
+          "due_date": { "type": "string", "format": "date-time", "nullable": true },
+          "completed_at": { "type": "string", "format": "date-time", "nullable": true },
+          "created_at": { "type": "string", "format": "date-time" },
+          "updated_at": { "type": "string", "format": "date-time" },
+          "owner_id": { "type": "string", "format": "uuid" },
+          "project_id": { "type": "string", "format": "uuid", "nullable": true },
+          "parent_id": { "type": "string", "format": "uuid", "nullable": true },
+          "subtasks": { "type": "array", "items": { "$ref": "#/components/schemas/Task" } },
+          "tags": { "type": "array", "items": { "$ref": "#/components/schemas/Tag" } },
+          "completion_percentage": { "type": "integer", "nullable": true }
+        }
+      },
+      "Project": {
+        "type": "object",
+        "required": ["id", "owner_id", "name", "color", "is_shared", "created_at", "updated_at"],
+        "properties": {
+          "id": { "type": "string", "format": "uuid" },
+          "owner_id": { "type": "string", "format": "uuid" },
+          "name": { "type": "string", "minLength": 1, "maxLength": 100 },
+          "color": { "type": "string", "pattern": "^#[0-9A-Fa-f]{6}$", "example": "#3B82F6" },
+          "is_shared": { "type": "boolean" },
+          "deadline": { "type": "string", "format": "date-time", "nullable": true },
+          "sort_order": { "type": "integer" },
+          "created_at": { "type": "string", "format": "date-time" },
+          "updated_at": { "type": "string", "format": "date-time" }
+        }
+      },
+      "Tag": {
+        "type": "object",
+        "required": ["id", "owner_id", "name", "color", "created_at"],
+        "properties": {
+          "id": { "type": "string", "format": "uuid" },
+          "owner_id": { "type": "string", "format": "uuid" },
+          "name": { "type": "string", "minLength": 1, "maxLength": 50 },
+          "color": { "type": "string", "pattern": "^#[0-9A-Fa-f]{6}$", "example": "#6B7280" },
+          "created_at": { "type": "string", "format": "date-time" }
+        }
+      },
+      "ProjectMember": {
+        "type": "object",
+        "required": ["user_id", "email", "role"],
+        "properties": {
+          "user_id": { "type": "string", "format": "uuid" },
+          "email": { "type": "string", "format": "email" },
+          "role": { "type": "string", "enum": ["owner", "editor", "viewer"] }
+        }
+      },
+      "TaskReminder": {
+        "type": "object",
+        "required": ["id", "task_id", "type", "scheduled_at", "created_at"],
+        "properties": {
+          "id": { "type": "string", "format": "uuid" },
+          "task_id": { "type": "string", "format": "uuid" },
+          "type": { "type": "string", "enum": ["push", "email", "webhook", "telegram", "nostr"] },
+          "config": { "type": "object", "additionalProperties": true },
+          "scheduled_at": { "type": "string", "format": "date-time" },
+          "created_at": { "type": "string", "format": "date-time" }
+        }
+      },
+      "TaskWebhook": {
+        "type": "object",
+        "required": ["id", "owner_id", "url", "events", "created_at"],
+        "properties": {
+          "id": { "type": "string", "format": "uuid" },
+          "owner_id": { "type": "string", "format": "uuid" },
+          "url": { "type": "string", "format": "uri" },
+          "events": { "type": "array", "items": { "type": "string", "enum": ["created", "status_change", "completion"] } },
+          "secret": { "type": "string", "nullable": true },
+          "created_at": { "type": "string", "format": "date-time" }
+        }
       }
     }
   }

internal/api/openapi/specs/tags.json

@@ -0,0 +1,198 @@
+{
+  "paths": {
+    "/tags": {
+      "get": {
+        "tags": ["Tags"],
+        "summary": "List tags",
+        "description": "Returns the authenticated user's tags. Requires `tasks:read` scope.",
+        "operationId": "listTags",
+        "parameters": [
+          { "name": "limit", "in": "query", "schema": { "type": "integer", "minimum": 1, "maximum": 200, "default": 50 } },
+          { "name": "cursor", "in": "query", "schema": { "type": "string" }, "description": "Pagination cursor" }
+        ],
+        "responses": {
+          "200": {
+            "description": "List of tags",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["items", "page"],
+                  "properties": {
+                    "items": { "type": "array", "items": { "$ref": "#/components/schemas/Tag" } },
+                    "page": { "$ref": "#/components/schemas/PageInfo" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "post": {
+        "tags": ["Tags"],
+        "summary": "Create a tag",
+        "description": "Creates a new tag for the authenticated user. Requires `tasks:write` scope.",
+        "operationId": "createTag",
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "required": ["name"],
+                "properties": {
+                  "name": { "type": "string", "minLength": 1, "maxLength": 50 },
+                  "color": { "type": "string", "pattern": "^#[0-9A-Fa-f]{6}$", "example": "#6B7280" }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Tag created",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["tag"],
+                  "properties": {
+                    "tag": { "$ref": "#/components/schemas/Tag" }
+                  }
+                }
+              }
+            }
+          },
+          "400": { "description": "Validation error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tags/{id}": {
+      "get": {
+        "tags": ["Tags"],
+        "summary": "Get a tag",
+        "description": "Returns a single tag by ID. Requires `tasks:read` scope.",
+        "operationId": "getTag",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": {
+            "description": "Tag details",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["tag"],
+                  "properties": {
+                    "tag": { "$ref": "#/components/schemas/Tag" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Tag not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "put": {
+        "tags": ["Tags"],
+        "summary": "Update a tag",
+        "description": "Updates a tag. Requires `tasks:write` scope.",
+        "operationId": "updateTag",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "properties": {
+                  "name": { "type": "string", "minLength": 1, "maxLength": 50 },
+                  "color": { "type": "string", "pattern": "^#[0-9A-Fa-f]{6}$" }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Tag updated",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["tag"],
+                  "properties": {
+                    "tag": { "$ref": "#/components/schemas/Tag" }
+                  }
+                }
+              }
+            }
+          },
+          "400": { "description": "Validation error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Tag not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "delete": {
+        "tags": ["Tags"],
+        "summary": "Delete a tag",
+        "description": "Deletes a tag. Requires `tasks:write` scope.",
+        "operationId": "deleteTag",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": { "description": "Tag deleted", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OkResponse" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Tag not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tags/{id}/attach/{taskId}": {
+      "post": {
+        "tags": ["Tags"],
+        "summary": "Attach tag to task",
+        "description": "Attaches a tag to a task. Requires `tasks:write` scope.",
+        "operationId": "attachTagToTask",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" }, "description": "Tag ID" },
+          { "name": "taskId", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" }, "description": "Task ID" }
+        ],
+        "responses": {
+          "200": { "description": "Tag attached", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OkResponse" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Tag or task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tags/{id}/detach/{taskId}": {
+      "delete": {
+        "tags": ["Tags"],
+        "summary": "Detach tag from task",
+        "description": "Removes a tag from a task. Requires `tasks:write` scope.",
+        "operationId": "detachTagFromTask",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" }, "description": "Tag ID" },
+          { "name": "taskId", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" }, "description": "Task ID" }
+        ],
+        "responses": {
+          "200": { "description": "Tag detached", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OkResponse" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Tag or task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    }
+  }
+}

internal/api/openapi/specs/tasks.json

@@ -0,0 +1,459 @@
+{
+  "paths": {
+    "/tasks": {
+      "get": {
+        "tags": ["Tasks"],
+        "summary": "List tasks",
+        "description": "Returns the authenticated user's tasks with optional filters. Supports status, priority, due date range, project, and cursor-based pagination. Requires `tasks:read` scope.",
+        "operationId": "listTasks",
+        "parameters": [
+          { "name": "status", "in": "query", "schema": { "type": "string", "enum": ["todo", "in_progress", "done", "archived"] }, "description": "Filter by status" },
+          { "name": "priority", "in": "query", "schema": { "type": "string", "enum": ["low", "medium", "high", "critical"] }, "description": "Filter by priority" },
+          { "name": "project_id", "in": "query", "schema": { "type": "string", "format": "uuid" }, "description": "Filter by project" },
+          { "name": "due_from", "in": "query", "schema": { "type": "string", "format": "date-time" }, "description": "Filter tasks due on or after" },
+          { "name": "due_to", "in": "query", "schema": { "type": "string", "format": "date-time" }, "description": "Filter tasks due on or before" },
+          { "name": "limit", "in": "query", "schema": { "type": "integer", "minimum": 1, "maximum": 200, "default": 50 } },
+          { "name": "cursor", "in": "query", "schema": { "type": "string" }, "description": "Pagination cursor" }
+        ],
+        "responses": {
+          "200": {
+            "description": "List of tasks",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["items", "page"],
+                  "properties": {
+                    "items": { "type": "array", "items": { "$ref": "#/components/schemas/Task" } },
+                    "page": { "$ref": "#/components/schemas/PageInfo" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "post": {
+        "tags": ["Tasks"],
+        "summary": "Create a task",
+        "description": "Creates a new task for the authenticated user. Requires `tasks:write` scope.",
+        "operationId": "createTask",
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "required": ["title"],
+                "properties": {
+                  "title": { "type": "string", "minLength": 1, "maxLength": 500 },
+                  "description": { "type": "string" },
+                  "status": { "type": "string", "enum": ["todo", "in_progress", "done", "archived"], "default": "todo" },
+                  "priority": { "type": "string", "enum": ["low", "medium", "high", "critical"], "default": "medium" },
+                  "due_date": { "type": "string", "format": "date-time" },
+                  "project_id": { "type": "string", "format": "uuid" },
+                  "parent_id": { "type": "string", "format": "uuid" },
+                  "sort_order": { "type": "integer" },
+                  "recurrence_rule": { "type": "string" }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Task created",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["task"],
+                  "properties": {
+                    "task": { "$ref": "#/components/schemas/Task" }
+                  }
+                }
+              }
+            }
+          },
+          "400": { "description": "Validation error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tasks/{id}": {
+      "get": {
+        "tags": ["Tasks"],
+        "summary": "Get a task",
+        "description": "Returns a single task by ID. Requires `tasks:read` scope.",
+        "operationId": "getTask",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": {
+            "description": "Task details",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["task"],
+                  "properties": {
+                    "task": { "$ref": "#/components/schemas/Task" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "put": {
+        "tags": ["Tasks"],
+        "summary": "Update a task",
+        "description": "Updates a task's fields. Requires `tasks:write` scope.",
+        "operationId": "updateTask",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "properties": {
+                  "title": { "type": "string", "minLength": 1, "maxLength": 500 },
+                  "description": { "type": "string" },
+                  "status": { "type": "string", "enum": ["todo", "in_progress", "done", "archived"] },
+                  "priority": { "type": "string", "enum": ["low", "medium", "high", "critical"] },
+                  "due_date": { "type": "string", "format": "date-time" },
+                  "project_id": { "type": "string", "format": "uuid", "nullable": true },
+                  "sort_order": { "type": "integer" },
+                  "recurrence_rule": { "type": "string", "nullable": true }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Task updated",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["task"],
+                  "properties": {
+                    "task": { "$ref": "#/components/schemas/Task" }
+                  }
+                }
+              }
+            }
+          },
+          "400": { "description": "Validation error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "delete": {
+        "tags": ["Tasks"],
+        "summary": "Delete a task",
+        "description": "Soft-deletes a task by default. Use `?permanent=true` for hard delete. Requires `tasks:write` scope.",
+        "operationId": "deleteTask",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } },
+          { "name": "permanent", "in": "query", "schema": { "type": "boolean", "default": false }, "description": "If true, permanently delete (hard delete)" }
+        ],
+        "responses": {
+          "200": { "description": "Task deleted", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OkResponse" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tasks/{id}/complete": {
+      "post": {
+        "tags": ["Tasks"],
+        "summary": "Mark task complete",
+        "description": "Marks a task as done. Fails if blocked by incomplete dependencies. Requires `tasks:write` scope.",
+        "operationId": "markTaskComplete",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": {
+            "description": "Task marked complete",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["task"],
+                  "properties": {
+                    "task": { "$ref": "#/components/schemas/Task" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "409": { "description": "Blocked by incomplete dependencies", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tasks/{id}/uncomplete": {
+      "post": {
+        "tags": ["Tasks"],
+        "summary": "Mark task uncomplete",
+        "description": "Reverts a completed task to todo (or specified status). Requires `tasks:write` scope.",
+        "operationId": "markTaskUncomplete",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "properties": {
+                  "status": { "type": "string", "enum": ["todo", "in_progress"], "default": "todo" }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Task marked uncomplete",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["task"],
+                  "properties": {
+                    "task": { "$ref": "#/components/schemas/Task" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tasks/{id}/subtasks": {
+      "get": {
+        "tags": ["Tasks"],
+        "summary": "List subtasks",
+        "description": "Returns the subtasks of a task. Requires `tasks:read` scope.",
+        "operationId": "listTaskSubtasks",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": {
+            "description": "List of subtasks",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["items", "page"],
+                  "properties": {
+                    "items": { "type": "array", "items": { "$ref": "#/components/schemas/Task" } },
+                    "page": { "$ref": "#/components/schemas/PageInfo" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tasks/{id}/dependencies": {
+      "get": {
+        "tags": ["Tasks"],
+        "summary": "List task blockers",
+        "description": "Returns tasks that block this task from being completed. Requires `tasks:read` scope.",
+        "operationId": "listTaskBlockers",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": {
+            "description": "List of blocking tasks",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["items", "page"],
+                  "properties": {
+                    "items": { "type": "array", "items": { "$ref": "#/components/schemas/Task" } },
+                    "page": { "$ref": "#/components/schemas/PageInfo" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "post": {
+        "tags": ["Tasks"],
+        "summary": "Add dependency",
+        "description": "Adds a dependency: the specified task blocks this task. Requires `tasks:write` scope.",
+        "operationId": "addTaskDependency",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" }, "description": "Task ID (blocked task)" }
+        ],
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "required": ["blocks_task_id"],
+                "properties": {
+                  "blocks_task_id": { "type": "string", "format": "uuid", "description": "Task that blocks this one" }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": { "description": "Dependency added", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OkResponse" } } } },
+          "400": { "description": "Validation error (e.g. self-dependency)", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "409": { "description": "Circular dependency detected", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tasks/{id}/dependencies/{blocksTaskId}": {
+      "delete": {
+        "tags": ["Tasks"],
+        "summary": "Remove dependency",
+        "description": "Removes a dependency. Requires `tasks:write` scope.",
+        "operationId": "removeTaskDependency",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" }, "description": "Task ID (blocked task)" },
+          { "name": "blocksTaskId", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" }, "description": "Blocker task ID" }
+        ],
+        "responses": {
+          "200": { "description": "Dependency removed", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OkResponse" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tasks/{id}/reminders": {
+      "get": {
+        "tags": ["Tasks"],
+        "summary": "List task reminders",
+        "description": "Returns reminders for a task. Requires `tasks:read` scope.",
+        "operationId": "listTaskReminders",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": {
+            "description": "List of reminders",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["items", "page"],
+                  "properties": {
+                    "items": { "type": "array", "items": { "$ref": "#/components/schemas/TaskReminder" } },
+                    "page": { "$ref": "#/components/schemas/PageInfo" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "post": {
+        "tags": ["Tasks"],
+        "summary": "Add task reminder",
+        "description": "Creates a reminder for a task. Requires `tasks:write` scope.",
+        "operationId": "addTaskReminder",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "required": ["type", "scheduled_at"],
+                "properties": {
+                  "type": { "type": "string", "enum": ["push", "email", "webhook", "telegram", "nostr"] },
+                  "config": { "type": "object", "additionalProperties": true },
+                  "scheduled_at": { "type": "string", "format": "date-time" }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Reminder created",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["reminder"],
+                  "properties": {
+                    "reminder": { "$ref": "#/components/schemas/TaskReminder" }
+                  }
+                }
+              }
+            }
+          },
+          "400": { "description": "Validation error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/tasks/{id}/reminders/{reminderId}": {
+      "delete": {
+        "tags": ["Tasks"],
+        "summary": "Delete task reminder",
+        "description": "Deletes a reminder. Requires `tasks:write` scope.",
+        "operationId": "deleteTaskReminder",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" }, "description": "Task ID" },
+          { "name": "reminderId", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" }, "description": "Reminder ID" }
+        ],
+        "responses": {
+          "200": { "description": "Reminder deleted", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OkResponse" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Task or reminder not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    }
+  }
+}

internal/api/openapi/specs/webhooks.json

@@ -0,0 +1,96 @@
+{
+  "paths": {
+    "/webhooks": {
+      "get": {
+        "tags": ["Webhooks"],
+        "summary": "List task webhooks",
+        "description": "Returns the authenticated user's task webhooks. Requires `tasks:read` scope.",
+        "operationId": "listTaskWebhooks",
+        "parameters": [
+          { "name": "limit", "in": "query", "schema": { "type": "integer", "minimum": 1, "maximum": 200, "default": 50 } },
+          { "name": "cursor", "in": "query", "schema": { "type": "string" }, "description": "Pagination cursor" }
+        ],
+        "responses": {
+          "200": {
+            "description": "List of webhooks",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["items", "page"],
+                  "properties": {
+                    "items": { "type": "array", "items": { "$ref": "#/components/schemas/TaskWebhook" } },
+                    "page": { "$ref": "#/components/schemas/PageInfo" }
+                  }
+                }
+              }
+            }
+          },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      },
+      "post": {
+        "tags": ["Webhooks"],
+        "summary": "Create task webhook",
+        "description": "Creates a webhook that receives task events (created, status_change, completion). Requires `tasks:write` scope.",
+        "operationId": "createTaskWebhook",
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "required": ["url", "events"],
+                "properties": {
+                  "url": { "type": "string", "format": "uri", "description": "Webhook endpoint URL" },
+                  "events": {
+                    "type": "array",
+                    "items": { "type": "string", "enum": ["created", "status_change", "completion"] },
+                    "description": "Events to subscribe to"
+                  }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Webhook created",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "required": ["webhook"],
+                  "properties": {
+                    "webhook": { "$ref": "#/components/schemas/TaskWebhook" }
+                  }
+                }
+              }
+            }
+          },
+          "400": { "description": "Validation error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    },
+    "/webhooks/{id}": {
+      "delete": {
+        "tags": ["Webhooks"],
+        "summary": "Delete task webhook",
+        "description": "Deletes a task webhook. Requires `tasks:write` scope.",
+        "operationId": "deleteTaskWebhook",
+        "parameters": [
+          { "name": "id", "in": "path", "required": true, "schema": { "type": "string", "format": "uuid" } }
+        ],
+        "responses": {
+          "200": { "description": "Webhook deleted", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OkResponse" } } } },
+          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "403": { "description": "Insufficient scope", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
+          "404": { "description": "Webhook not found", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
+        }
+      }
+    }
+  }
+}

internal/api/routes.go

@@ -13,18 +13,24 @@ import (
 )
 
 type Handlers struct {
-	Auth         *handlers.AuthHandler
-	User         *handlers.UserHandler
-	Calendar     *handlers.CalendarHandler
-	Sharing      *handlers.SharingHandler
-	Event        *handlers.EventHandler
-	Reminder     *handlers.ReminderHandler
-	Attendee     *handlers.AttendeeHandler
-	Contact      *handlers.ContactHandler
-	Availability *handlers.AvailabilityHandler
-	Booking      *handlers.BookingHandler
-	APIKey       *handlers.APIKeyHandler
-	ICS          *handlers.ICSHandler
+	Auth            *handlers.AuthHandler
+	User            *handlers.UserHandler
+	Calendar        *handlers.CalendarHandler
+	Sharing         *handlers.SharingHandler
+	Event           *handlers.EventHandler
+	Reminder        *handlers.ReminderHandler
+	Attendee        *handlers.AttendeeHandler
+	Contact         *handlers.ContactHandler
+	Availability    *handlers.AvailabilityHandler
+	Booking         *handlers.BookingHandler
+	APIKey          *handlers.APIKeyHandler
+	ICS             *handlers.ICSHandler
+	Task            *handlers.TaskHandler
+	Project         *handlers.ProjectHandler
+	Tag             *handlers.TagHandler
+	TaskDependency  *handlers.TaskDependencyHandler
+	TaskReminder    *handlers.TaskReminderHandler
+	TaskWebhook     *handlers.TaskWebhookHandler
 }
 
 func NewRouter(h Handlers, authMW *mw.AuthMiddleware, rateLimiter *mw.RateLimiter, cfg *config.Config) *chi.Mux {
@@ -152,6 +158,68 @@ func NewRouter(h Handlers, authMW *mw.AuthMiddleware, rateLimiter *mw.RateLimite
 			})
 		})
 
+		// Tasks
+		r.Route("/tasks", func(r chi.Router) {
+			r.With(mw.RequireScope("tasks", "read")).Get("/", h.Task.List)
+			r.With(mw.RequireScope("tasks", "write")).Post("/", h.Task.Create)
+
+			r.Route("/{id}", func(r chi.Router) {
+				r.With(mw.RequireScope("tasks", "read")).Get("/", h.Task.Get)
+				r.With(mw.RequireScope("tasks", "write")).Put("/", h.Task.Update)
+				r.With(mw.RequireScope("tasks", "write")).Delete("/", h.Task.Delete)
+				r.With(mw.RequireScope("tasks", "write")).Post("/complete", h.Task.MarkComplete)
+				r.With(mw.RequireScope("tasks", "write")).Post("/uncomplete", h.Task.MarkUncomplete)
+				r.With(mw.RequireScope("tasks", "read")).Get("/subtasks", h.Task.ListSubtasks)
+
+				r.Route("/dependencies", func(r chi.Router) {
+					r.With(mw.RequireScope("tasks", "read")).Get("/", h.TaskDependency.ListBlockers)
+					r.With(mw.RequireScope("tasks", "write")).Post("/", h.TaskDependency.Add)
+					r.With(mw.RequireScope("tasks", "write")).Delete("/{blocksTaskId}", h.TaskDependency.Remove)
+				})
+
+				r.Route("/reminders", func(r chi.Router) {
+					r.With(mw.RequireScope("tasks", "read")).Get("/", h.TaskReminder.List)
+					r.With(mw.RequireScope("tasks", "write")).Post("/", h.TaskReminder.Add)
+					r.With(mw.RequireScope("tasks", "write")).Delete("/{reminderId}", h.TaskReminder.Delete)
+				})
+			})
+		})
+
+		// Projects
+		r.Route("/projects", func(r chi.Router) {
+			r.With(mw.RequireScope("tasks", "read")).Get("/", h.Project.List)
+			r.With(mw.RequireScope("tasks", "write")).Post("/", h.Project.Create)
+
+			r.Route("/{id}", func(r chi.Router) {
+				r.With(mw.RequireScope("tasks", "read")).Get("/", h.Project.Get)
+				r.With(mw.RequireScope("tasks", "write")).Put("/", h.Project.Update)
+				r.With(mw.RequireScope("tasks", "write")).Delete("/", h.Project.Delete)
+				r.With(mw.RequireScope("tasks", "write")).Post("/share", h.Project.Share)
+				r.With(mw.RequireScope("tasks", "read")).Get("/members", h.Project.ListMembers)
+			})
+		})
+
+		// Tags
+		r.Route("/tags", func(r chi.Router) {
+			r.With(mw.RequireScope("tasks", "read")).Get("/", h.Tag.List)
+			r.With(mw.RequireScope("tasks", "write")).Post("/", h.Tag.Create)
+
+			r.Route("/{id}", func(r chi.Router) {
+				r.With(mw.RequireScope("tasks", "read")).Get("/", h.Tag.Get)
+				r.With(mw.RequireScope("tasks", "write")).Put("/", h.Tag.Update)
+				r.With(mw.RequireScope("tasks", "write")).Delete("/", h.Tag.Delete)
+				r.With(mw.RequireScope("tasks", "write")).Post("/attach/{taskId}", h.Tag.AttachToTask)
+				r.With(mw.RequireScope("tasks", "write")).Delete("/detach/{taskId}", h.Tag.DetachFromTask)
+			})
+		})
+
+		// Task Webhooks
+		r.Route("/webhooks", func(r chi.Router) {
+			r.With(mw.RequireScope("tasks", "read")).Get("/", h.TaskWebhook.List)
+			r.With(mw.RequireScope("tasks", "write")).Post("/", h.TaskWebhook.Create)
+			r.With(mw.RequireScope("tasks", "write")).Delete("/{id}", h.TaskWebhook.Delete)
+		})
+
 		// Availability
 		r.With(mw.RequireScope("availability", "read")).Get("/availability", h.Availability.Get)
 	})

internal/config/config.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"log"
 	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 )
@@ -21,7 +22,7 @@ type Config struct {
 }
 
 func Load() *Config {
-	loadEnvFile(".env")
+	loadEnvFromPath()
 
 	port := getEnv("SERVER_PORT", "8080")
 	jwtSecret := getEnv("JWT_SECRET", "dev-secret-change-me")
@@ -41,7 +42,7 @@ func Load() *Config {
 		RedisAddr:      os.Getenv("REDIS_ADDR"),
 		ServerPort:     port,
 		Env:            env,
-		BaseURL:        getEnv("BASE_URL", "http://localhost:"+port),
+		BaseURL:        strings.TrimSuffix(getEnv("BASE_URL", "http://localhost:"+port), "/"),
 		CORSOrigins:    corsOrigins,
 		RateLimitRPS:   rateRPS,
 		RateLimitBurst: rateBurst,
@@ -82,6 +83,24 @@ func parseInt(s string, def int) int {
 	return v
 }
 
+func loadEnvFromPath() {
+	if p := os.Getenv("ENV_FILE"); p != "" {
+		loadEnvFile(p)
+		return
+	}
+	cwd, _ := os.Getwd()
+	for _, p := range []string{".env", "../.env"} {
+		full := filepath.Join(cwd, p)
+		if f, err := os.Open(full); err == nil {
+			f.Close()
+			loadEnvFile(full)
+			return
+		}
+	}
+	// Fallback: try current dir as-is (for relative paths)
+	loadEnvFile(".env")
+}
+
 func loadEnvFile(path string) {
 	f, err := os.Open(path)
 	if err != nil {

internal/models/models.go

@@ -79,6 +79,70 @@ type Attachment struct {
 	FileURL string    `json:"file_url"`
 }
 
+type Task struct {
+	ID                  uuid.UUID  `json:"id"`
+	OwnerID             uuid.UUID  `json:"owner_id"`
+	Title               string     `json:"title"`
+	Description         *string    `json:"description"`
+	Status              string     `json:"status"`
+	Priority            string     `json:"priority"`
+	DueDate             *time.Time `json:"due_date"`
+	CompletedAt         *time.Time `json:"completed_at"`
+	CreatedAt           time.Time  `json:"created_at"`
+	UpdatedAt           time.Time  `json:"updated_at"`
+	ProjectID           *uuid.UUID `json:"project_id"`
+	ParentID            *uuid.UUID `json:"parent_id"`
+	SortOrder           int       `json:"sort_order"`
+	RecurrenceRule      *string    `json:"recurrence_rule"`
+	Subtasks            []Task    `json:"subtasks,omitempty"`
+	Tags                []Tag     `json:"tags,omitempty"`
+	CompletionPercentage *int     `json:"completion_percentage,omitempty"`
+}
+
+type Project struct {
+	ID        uuid.UUID  `json:"id"`
+	OwnerID   uuid.UUID  `json:"owner_id"`
+	Name      string     `json:"name"`
+	Color     string     `json:"color"`
+	IsShared  bool       `json:"is_shared"`
+	Deadline  *time.Time `json:"deadline"`
+	SortOrder int        `json:"sort_order"`
+	CreatedAt time.Time  `json:"created_at"`
+	UpdatedAt time.Time  `json:"updated_at"`
+}
+
+type ProjectMember struct {
+	UserID uuid.UUID `json:"user_id"`
+	Email  string    `json:"email"`
+	Role   string    `json:"role"`
+}
+
+type TaskWebhook struct {
+	ID        uuid.UUID  `json:"id"`
+	OwnerID   uuid.UUID  `json:"owner_id"`
+	URL       string     `json:"url"`
+	Events    []string   `json:"events"`
+	Secret    *string    `json:"secret,omitempty"`
+	CreatedAt time.Time  `json:"created_at"`
+}
+
+type TaskReminder struct {
+	ID          uuid.UUID              `json:"id"`
+	TaskID      uuid.UUID              `json:"task_id"`
+	Type        string                 `json:"type"`
+	Config      map[string]interface{} `json:"config"`
+	ScheduledAt time.Time              `json:"scheduled_at"`
+	CreatedAt   time.Time              `json:"created_at"`
+}
+
+type Tag struct {
+	ID        uuid.UUID `json:"id"`
+	OwnerID   uuid.UUID `json:"owner_id"`
+	Name      string    `json:"name"`
+	Color     string    `json:"color"`
+	CreatedAt time.Time `json:"created_at"`
+}
+
 type Contact struct {
 	ID        uuid.UUID  `json:"id"`
 	FirstName *string    `json:"first_name"`

internal/repository/calendars.sql.go

@@ -199,7 +199,7 @@ SELECT c.id, c.owner_id, c.name, c.color, c.is_public, c.count_for_availability,
 FROM calendars c
 JOIN calendar_members cm ON cm.calendar_id = c.id
 WHERE cm.user_id = $1 AND c.deleted_at IS NULL
-ORDER BY c.created_at ASC
+ORDER BY c.sort_order ASC, c.created_at ASC
 `
 
 type ListCalendarsByUserRow struct {

internal/repository/models.go

@@ -130,6 +130,25 @@ type EventReminder struct {
 	MinutesBefore int32       `json:"minutes_before"`
 }
 
+type Project struct {
+	ID        pgtype.UUID        `json:"id"`
+	OwnerID   pgtype.UUID        `json:"owner_id"`
+	Name      string             `json:"name"`
+	Color     string             `json:"color"`
+	IsShared  bool               `json:"is_shared"`
+	Deadline  pgtype.Timestamptz `json:"deadline"`
+	SortOrder int32              `json:"sort_order"`
+	CreatedAt pgtype.Timestamptz `json:"created_at"`
+	UpdatedAt pgtype.Timestamptz `json:"updated_at"`
+	DeletedAt pgtype.Timestamptz `json:"deleted_at"`
+}
+
+type ProjectMember struct {
+	ProjectID pgtype.UUID `json:"project_id"`
+	UserID    pgtype.UUID `json:"user_id"`
+	Role      string      `json:"role"`
+}
+
 type RefreshToken struct {
 	ID        pgtype.UUID        `json:"id"`
 	UserID    pgtype.UUID        `json:"user_id"`
@@ -139,6 +158,60 @@ type RefreshToken struct {
 	CreatedAt pgtype.Timestamptz `json:"created_at"`
 }
 
+type Tag struct {
+	ID        pgtype.UUID        `json:"id"`
+	OwnerID   pgtype.UUID        `json:"owner_id"`
+	Name      string             `json:"name"`
+	Color     string             `json:"color"`
+	CreatedAt pgtype.Timestamptz `json:"created_at"`
+}
+
+type Task struct {
+	ID             pgtype.UUID        `json:"id"`
+	OwnerID        pgtype.UUID        `json:"owner_id"`
+	Title          string             `json:"title"`
+	Description    pgtype.Text        `json:"description"`
+	Status         string             `json:"status"`
+	Priority       string             `json:"priority"`
+	DueDate        pgtype.Timestamptz `json:"due_date"`
+	CompletedAt    pgtype.Timestamptz `json:"completed_at"`
+	CreatedAt      pgtype.Timestamptz `json:"created_at"`
+	UpdatedAt      pgtype.Timestamptz `json:"updated_at"`
+	DeletedAt      pgtype.Timestamptz `json:"deleted_at"`
+	ProjectID      pgtype.UUID        `json:"project_id"`
+	ParentID       pgtype.UUID        `json:"parent_id"`
+	SortOrder      int32              `json:"sort_order"`
+	RecurrenceRule pgtype.Text        `json:"recurrence_rule"`
+}
+
+type TaskDependency struct {
+	TaskID       pgtype.UUID `json:"task_id"`
+	BlocksTaskID pgtype.UUID `json:"blocks_task_id"`
+}
+
+type TaskReminder struct {
+	ID          pgtype.UUID        `json:"id"`
+	TaskID      pgtype.UUID        `json:"task_id"`
+	Type        string             `json:"type"`
+	Config      []byte             `json:"config"`
+	ScheduledAt pgtype.Timestamptz `json:"scheduled_at"`
+	CreatedAt   pgtype.Timestamptz `json:"created_at"`
+}
+
+type TaskTag struct {
+	TaskID pgtype.UUID `json:"task_id"`
+	TagID  pgtype.UUID `json:"tag_id"`
+}
+
+type TaskWebhook struct {
+	ID        pgtype.UUID        `json:"id"`
+	OwnerID   pgtype.UUID        `json:"owner_id"`
+	Url       string             `json:"url"`
+	Events    []byte             `json:"events"`
+	Secret    pgtype.Text        `json:"secret"`
+	CreatedAt pgtype.Timestamptz `json:"created_at"`
+}
+
 type User struct {
 	ID                          pgtype.UUID        `json:"id"`
 	Email                       string             `json:"email"`

internal/repository/projects.sql.go

@@ -0,0 +1,309 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+// source: projects.sql
+
+package repository
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+const addProjectMember = `-- name: AddProjectMember :exec
+INSERT INTO project_members (project_id, user_id, role)
+VALUES ($1, $2, $3)
+ON CONFLICT (project_id, user_id) DO UPDATE SET role = EXCLUDED.role
+`
+
+type AddProjectMemberParams struct {
+	ProjectID pgtype.UUID `json:"project_id"`
+	UserID    pgtype.UUID `json:"user_id"`
+	Role      string      `json:"role"`
+}
+
+func (q *Queries) AddProjectMember(ctx context.Context, arg AddProjectMemberParams) error {
+	_, err := q.db.Exec(ctx, addProjectMember, arg.ProjectID, arg.UserID, arg.Role)
+	return err
+}
+
+const createProject = `-- name: CreateProject :one
+INSERT INTO projects (id, owner_id, name, color, is_shared, deadline, sort_order)
+VALUES ($1, $2, $3, $4, COALESCE($5, false), $6, COALESCE($7, 0))
+RETURNING id, owner_id, name, color, is_shared, deadline, sort_order, created_at, updated_at, deleted_at
+`
+
+type CreateProjectParams struct {
+	ID       pgtype.UUID        `json:"id"`
+	OwnerID  pgtype.UUID        `json:"owner_id"`
+	Name     string             `json:"name"`
+	Color    string             `json:"color"`
+	Column5  interface{}        `json:"column_5"`
+	Deadline pgtype.Timestamptz `json:"deadline"`
+	Column7  interface{}        `json:"column_7"`
+}
+
+func (q *Queries) CreateProject(ctx context.Context, arg CreateProjectParams) (Project, error) {
+	row := q.db.QueryRow(ctx, createProject,
+		arg.ID,
+		arg.OwnerID,
+		arg.Name,
+		arg.Color,
+		arg.Column5,
+		arg.Deadline,
+		arg.Column7,
+	)
+	var i Project
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Name,
+		&i.Color,
+		&i.IsShared,
+		&i.Deadline,
+		&i.SortOrder,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.DeletedAt,
+	)
+	return i, err
+}
+
+const getProjectByID = `-- name: GetProjectByID :one
+SELECT id, owner_id, name, color, is_shared, deadline, sort_order, created_at, updated_at, deleted_at FROM projects
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL
+`
+
+type GetProjectByIDParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) GetProjectByID(ctx context.Context, arg GetProjectByIDParams) (Project, error) {
+	row := q.db.QueryRow(ctx, getProjectByID, arg.ID, arg.OwnerID)
+	var i Project
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Name,
+		&i.Color,
+		&i.IsShared,
+		&i.Deadline,
+		&i.SortOrder,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.DeletedAt,
+	)
+	return i, err
+}
+
+const getProjectMember = `-- name: GetProjectMember :one
+SELECT project_id, user_id, role FROM project_members
+WHERE project_id = $1 AND user_id = $2
+`
+
+type GetProjectMemberParams struct {
+	ProjectID pgtype.UUID `json:"project_id"`
+	UserID    pgtype.UUID `json:"user_id"`
+}
+
+func (q *Queries) GetProjectMember(ctx context.Context, arg GetProjectMemberParams) (ProjectMember, error) {
+	row := q.db.QueryRow(ctx, getProjectMember, arg.ProjectID, arg.UserID)
+	var i ProjectMember
+	err := row.Scan(&i.ProjectID, &i.UserID, &i.Role)
+	return i, err
+}
+
+const listProjectMembers = `-- name: ListProjectMembers :many
+SELECT pm.project_id, pm.user_id, pm.role, u.email
+FROM project_members pm
+JOIN users u ON u.id = pm.user_id
+WHERE pm.project_id = $1
+`
+
+type ListProjectMembersRow struct {
+	ProjectID pgtype.UUID `json:"project_id"`
+	UserID    pgtype.UUID `json:"user_id"`
+	Role      string      `json:"role"`
+	Email     string      `json:"email"`
+}
+
+func (q *Queries) ListProjectMembers(ctx context.Context, projectID pgtype.UUID) ([]ListProjectMembersRow, error) {
+	rows, err := q.db.Query(ctx, listProjectMembers, projectID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []ListProjectMembersRow{}
+	for rows.Next() {
+		var i ListProjectMembersRow
+		if err := rows.Scan(
+			&i.ProjectID,
+			&i.UserID,
+			&i.Role,
+			&i.Email,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listProjects = `-- name: ListProjects :many
+SELECT id, owner_id, name, color, is_shared, deadline, sort_order, created_at, updated_at, deleted_at FROM projects
+WHERE owner_id = $1 AND deleted_at IS NULL
+ORDER BY sort_order ASC, name ASC
+`
+
+func (q *Queries) ListProjects(ctx context.Context, ownerID pgtype.UUID) ([]Project, error) {
+	rows, err := q.db.Query(ctx, listProjects, ownerID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Project{}
+	for rows.Next() {
+		var i Project
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Name,
+			&i.Color,
+			&i.IsShared,
+			&i.Deadline,
+			&i.SortOrder,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.DeletedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listProjectsForUser = `-- name: ListProjectsForUser :many
+SELECT p.id, p.owner_id, p.name, p.color, p.is_shared, p.deadline, p.sort_order, p.created_at, p.updated_at, p.deleted_at FROM projects p
+LEFT JOIN project_members pm ON pm.project_id = p.id AND pm.user_id = $1
+WHERE (p.owner_id = $1 OR pm.user_id = $1)
+  AND p.deleted_at IS NULL
+ORDER BY p.sort_order ASC, p.name ASC
+`
+
+func (q *Queries) ListProjectsForUser(ctx context.Context, userID pgtype.UUID) ([]Project, error) {
+	rows, err := q.db.Query(ctx, listProjectsForUser, userID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Project{}
+	for rows.Next() {
+		var i Project
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Name,
+			&i.Color,
+			&i.IsShared,
+			&i.Deadline,
+			&i.SortOrder,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.DeletedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const removeProjectMember = `-- name: RemoveProjectMember :exec
+DELETE FROM project_members
+WHERE project_id = $1 AND user_id = $2
+`
+
+type RemoveProjectMemberParams struct {
+	ProjectID pgtype.UUID `json:"project_id"`
+	UserID    pgtype.UUID `json:"user_id"`
+}
+
+func (q *Queries) RemoveProjectMember(ctx context.Context, arg RemoveProjectMemberParams) error {
+	_, err := q.db.Exec(ctx, removeProjectMember, arg.ProjectID, arg.UserID)
+	return err
+}
+
+const softDeleteProject = `-- name: SoftDeleteProject :exec
+UPDATE projects SET deleted_at = now(), updated_at = now()
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL
+`
+
+type SoftDeleteProjectParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) SoftDeleteProject(ctx context.Context, arg SoftDeleteProjectParams) error {
+	_, err := q.db.Exec(ctx, softDeleteProject, arg.ID, arg.OwnerID)
+	return err
+}
+
+const updateProject = `-- name: UpdateProject :one
+UPDATE projects
+SET name = COALESCE($1, name),
+    color = COALESCE($2, color),
+    is_shared = COALESCE($3, is_shared),
+    deadline = $4,
+    sort_order = COALESCE($5, sort_order),
+    updated_at = now()
+WHERE id = $6 AND owner_id = $7 AND deleted_at IS NULL
+RETURNING id, owner_id, name, color, is_shared, deadline, sort_order, created_at, updated_at, deleted_at
+`
+
+type UpdateProjectParams struct {
+	Name      pgtype.Text        `json:"name"`
+	Color     pgtype.Text        `json:"color"`
+	IsShared  pgtype.Bool        `json:"is_shared"`
+	Deadline  pgtype.Timestamptz `json:"deadline"`
+	SortOrder pgtype.Int4        `json:"sort_order"`
+	ID        pgtype.UUID        `json:"id"`
+	OwnerID   pgtype.UUID        `json:"owner_id"`
+}
+
+func (q *Queries) UpdateProject(ctx context.Context, arg UpdateProjectParams) (Project, error) {
+	row := q.db.QueryRow(ctx, updateProject,
+		arg.Name,
+		arg.Color,
+		arg.IsShared,
+		arg.Deadline,
+		arg.SortOrder,
+		arg.ID,
+		arg.OwnerID,
+	)
+	var i Project
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Name,
+		&i.Color,
+		&i.IsShared,
+		&i.Deadline,
+		&i.SortOrder,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.DeletedAt,
+	)
+	return i, err
+}

internal/repository/subscriptions.sql.go

@@ -105,17 +105,6 @@ func (q *Queries) ListSubscriptionsByCalendar(ctx context.Context, calendarID pg
 	return items, nil
 }
 
-const updateSubscriptionLastSynced = `-- name: UpdateSubscriptionLastSynced :exec
-UPDATE calendar_subscriptions
-SET last_synced_at = now()
-WHERE id = $1
-`
-
-func (q *Queries) UpdateSubscriptionLastSynced(ctx context.Context, id pgtype.UUID) error {
-	_, err := q.db.Exec(ctx, updateSubscriptionLastSynced, id)
-	return err
-}
-
 const listSubscriptionsDueForSync = `-- name: ListSubscriptionsDueForSync :many
 SELECT s.id, s.calendar_id, s.source_url, c.owner_id
 FROM calendar_subscriptions s
@@ -139,10 +128,15 @@ func (q *Queries) ListSubscriptionsDueForSync(ctx context.Context) ([]ListSubscr
 		return nil, err
 	}
 	defer rows.Close()
-	var items []ListSubscriptionsDueForSyncRow
+	items := []ListSubscriptionsDueForSyncRow{}
 	for rows.Next() {
 		var i ListSubscriptionsDueForSyncRow
-		if err := rows.Scan(&i.ID, &i.CalendarID, &i.SourceUrl, &i.OwnerID); err != nil {
+		if err := rows.Scan(
+			&i.ID,
+			&i.CalendarID,
+			&i.SourceUrl,
+			&i.OwnerID,
+		); err != nil {
 			return nil, err
 		}
 		items = append(items, i)
@@ -152,3 +146,14 @@ func (q *Queries) ListSubscriptionsDueForSync(ctx context.Context) ([]ListSubscr
 	}
 	return items, nil
 }
+
+const updateSubscriptionLastSynced = `-- name: UpdateSubscriptionLastSynced :exec
+UPDATE calendar_subscriptions
+SET last_synced_at = now()
+WHERE id = $1
+`
+
+func (q *Queries) UpdateSubscriptionLastSynced(ctx context.Context, id pgtype.UUID) error {
+	_, err := q.db.Exec(ctx, updateSubscriptionLastSynced, id)
+	return err
+}

internal/repository/tags.sql.go

@@ -0,0 +1,232 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+// source: tags.sql
+
+package repository
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+const attachTagToTask = `-- name: AttachTagToTask :exec
+INSERT INTO task_tags (task_id, tag_id)
+VALUES ($1, $2)
+ON CONFLICT (task_id, tag_id) DO NOTHING
+`
+
+type AttachTagToTaskParams struct {
+	TaskID pgtype.UUID `json:"task_id"`
+	TagID  pgtype.UUID `json:"tag_id"`
+}
+
+func (q *Queries) AttachTagToTask(ctx context.Context, arg AttachTagToTaskParams) error {
+	_, err := q.db.Exec(ctx, attachTagToTask, arg.TaskID, arg.TagID)
+	return err
+}
+
+const createTag = `-- name: CreateTag :one
+INSERT INTO tags (id, owner_id, name, color)
+VALUES ($1, $2, $3, COALESCE($4, '#6B7280'))
+RETURNING id, owner_id, name, color, created_at
+`
+
+type CreateTagParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+	Name    string      `json:"name"`
+	Column4 interface{} `json:"column_4"`
+}
+
+func (q *Queries) CreateTag(ctx context.Context, arg CreateTagParams) (Tag, error) {
+	row := q.db.QueryRow(ctx, createTag,
+		arg.ID,
+		arg.OwnerID,
+		arg.Name,
+		arg.Column4,
+	)
+	var i Tag
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Name,
+		&i.Color,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const deleteTag = `-- name: DeleteTag :exec
+DELETE FROM tags WHERE id = $1 AND owner_id = $2
+`
+
+type DeleteTagParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) DeleteTag(ctx context.Context, arg DeleteTagParams) error {
+	_, err := q.db.Exec(ctx, deleteTag, arg.ID, arg.OwnerID)
+	return err
+}
+
+const detachTagFromTask = `-- name: DetachTagFromTask :exec
+DELETE FROM task_tags
+WHERE task_id = $1 AND tag_id = $2
+`
+
+type DetachTagFromTaskParams struct {
+	TaskID pgtype.UUID `json:"task_id"`
+	TagID  pgtype.UUID `json:"tag_id"`
+}
+
+func (q *Queries) DetachTagFromTask(ctx context.Context, arg DetachTagFromTaskParams) error {
+	_, err := q.db.Exec(ctx, detachTagFromTask, arg.TaskID, arg.TagID)
+	return err
+}
+
+const getTagByID = `-- name: GetTagByID :one
+SELECT id, owner_id, name, color, created_at FROM tags
+WHERE id = $1 AND owner_id = $2
+`
+
+type GetTagByIDParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) GetTagByID(ctx context.Context, arg GetTagByIDParams) (Tag, error) {
+	row := q.db.QueryRow(ctx, getTagByID, arg.ID, arg.OwnerID)
+	var i Tag
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Name,
+		&i.Color,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const listTagsByOwner = `-- name: ListTagsByOwner :many
+SELECT id, owner_id, name, color, created_at FROM tags
+WHERE owner_id = $1
+ORDER BY name ASC
+`
+
+func (q *Queries) ListTagsByOwner(ctx context.Context, ownerID pgtype.UUID) ([]Tag, error) {
+	rows, err := q.db.Query(ctx, listTagsByOwner, ownerID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Tag{}
+	for rows.Next() {
+		var i Tag
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Name,
+			&i.Color,
+			&i.CreatedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listTagsByTask = `-- name: ListTagsByTask :many
+SELECT t.id, t.owner_id, t.name, t.color, t.created_at FROM tags t
+JOIN task_tags tt ON tt.tag_id = t.id
+WHERE tt.task_id = $1
+`
+
+func (q *Queries) ListTagsByTask(ctx context.Context, taskID pgtype.UUID) ([]Tag, error) {
+	rows, err := q.db.Query(ctx, listTagsByTask, taskID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Tag{}
+	for rows.Next() {
+		var i Tag
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Name,
+			&i.Color,
+			&i.CreatedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listTaskIDsByTag = `-- name: ListTaskIDsByTag :many
+SELECT task_id FROM task_tags WHERE tag_id = $1
+`
+
+func (q *Queries) ListTaskIDsByTag(ctx context.Context, tagID pgtype.UUID) ([]pgtype.UUID, error) {
+	rows, err := q.db.Query(ctx, listTaskIDsByTag, tagID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []pgtype.UUID{}
+	for rows.Next() {
+		var task_id pgtype.UUID
+		if err := rows.Scan(&task_id); err != nil {
+			return nil, err
+		}
+		items = append(items, task_id)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const updateTag = `-- name: UpdateTag :one
+UPDATE tags
+SET name = COALESCE($1, name),
+    color = COALESCE($2, color)
+WHERE id = $3 AND owner_id = $4
+RETURNING id, owner_id, name, color, created_at
+`
+
+type UpdateTagParams struct {
+	Name    pgtype.Text `json:"name"`
+	Color   pgtype.Text `json:"color"`
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) UpdateTag(ctx context.Context, arg UpdateTagParams) (Tag, error) {
+	row := q.db.QueryRow(ctx, updateTag,
+		arg.Name,
+		arg.Color,
+		arg.ID,
+		arg.OwnerID,
+	)
+	var i Tag
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Name,
+		&i.Color,
+		&i.CreatedAt,
+	)
+	return i, err
+}

internal/repository/task_dependencies.sql.go

@@ -0,0 +1,147 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+// source: task_dependencies.sql
+
+package repository
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+const addTaskDependency = `-- name: AddTaskDependency :exec
+INSERT INTO task_dependencies (task_id, blocks_task_id)
+VALUES ($1, $2)
+ON CONFLICT (task_id, blocks_task_id) DO NOTHING
+`
+
+type AddTaskDependencyParams struct {
+	TaskID       pgtype.UUID `json:"task_id"`
+	BlocksTaskID pgtype.UUID `json:"blocks_task_id"`
+}
+
+func (q *Queries) AddTaskDependency(ctx context.Context, arg AddTaskDependencyParams) error {
+	_, err := q.db.Exec(ctx, addTaskDependency, arg.TaskID, arg.BlocksTaskID)
+	return err
+}
+
+const checkDirectCircularDependency = `-- name: CheckDirectCircularDependency :one
+SELECT EXISTS(
+  SELECT 1 FROM task_dependencies
+  WHERE task_id = $2 AND blocks_task_id = $1
+) AS has_circle
+`
+
+type CheckDirectCircularDependencyParams struct {
+	BlocksTaskID pgtype.UUID `json:"blocks_task_id"`
+	TaskID       pgtype.UUID `json:"task_id"`
+}
+
+// Direct cycle: blocks_task_id is blocked by task_id (would create A->B and B->A)
+func (q *Queries) CheckDirectCircularDependency(ctx context.Context, arg CheckDirectCircularDependencyParams) (bool, error) {
+	row := q.db.QueryRow(ctx, checkDirectCircularDependency, arg.BlocksTaskID, arg.TaskID)
+	var has_circle bool
+	err := row.Scan(&has_circle)
+	return has_circle, err
+}
+
+const listTaskBlockers = `-- name: ListTaskBlockers :many
+SELECT t.id, t.owner_id, t.title, t.description, t.status, t.priority, t.due_date, t.completed_at, t.created_at, t.updated_at, t.deleted_at, t.project_id, t.parent_id, t.sort_order, t.recurrence_rule FROM tasks t
+JOIN task_dependencies td ON td.blocks_task_id = t.id
+WHERE td.task_id = $1 AND t.deleted_at IS NULL
+`
+
+func (q *Queries) ListTaskBlockers(ctx context.Context, taskID pgtype.UUID) ([]Task, error) {
+	rows, err := q.db.Query(ctx, listTaskBlockers, taskID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Task{}
+	for rows.Next() {
+		var i Task
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Title,
+			&i.Description,
+			&i.Status,
+			&i.Priority,
+			&i.DueDate,
+			&i.CompletedAt,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.DeletedAt,
+			&i.ProjectID,
+			&i.ParentID,
+			&i.SortOrder,
+			&i.RecurrenceRule,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listTasksBlockedBy = `-- name: ListTasksBlockedBy :many
+SELECT t.id, t.owner_id, t.title, t.description, t.status, t.priority, t.due_date, t.completed_at, t.created_at, t.updated_at, t.deleted_at, t.project_id, t.parent_id, t.sort_order, t.recurrence_rule FROM tasks t
+JOIN task_dependencies td ON td.task_id = t.id
+WHERE td.blocks_task_id = $1 AND t.deleted_at IS NULL
+`
+
+func (q *Queries) ListTasksBlockedBy(ctx context.Context, blocksTaskID pgtype.UUID) ([]Task, error) {
+	rows, err := q.db.Query(ctx, listTasksBlockedBy, blocksTaskID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Task{}
+	for rows.Next() {
+		var i Task
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Title,
+			&i.Description,
+			&i.Status,
+			&i.Priority,
+			&i.DueDate,
+			&i.CompletedAt,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.DeletedAt,
+			&i.ProjectID,
+			&i.ParentID,
+			&i.SortOrder,
+			&i.RecurrenceRule,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const removeTaskDependency = `-- name: RemoveTaskDependency :exec
+DELETE FROM task_dependencies
+WHERE task_id = $1 AND blocks_task_id = $2
+`
+
+type RemoveTaskDependencyParams struct {
+	TaskID       pgtype.UUID `json:"task_id"`
+	BlocksTaskID pgtype.UUID `json:"blocks_task_id"`
+}
+
+func (q *Queries) RemoveTaskDependency(ctx context.Context, arg RemoveTaskDependencyParams) error {
+	_, err := q.db.Exec(ctx, removeTaskDependency, arg.TaskID, arg.BlocksTaskID)
+	return err
+}

internal/repository/task_reminders.sql.go

@@ -0,0 +1,164 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+// source: task_reminders.sql
+
+package repository
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+const createTaskReminder = `-- name: CreateTaskReminder :one
+INSERT INTO task_reminders (id, task_id, type, config, scheduled_at)
+VALUES ($1, $2, $3, COALESCE($4, '{}'), $5)
+RETURNING id, task_id, type, config, scheduled_at, created_at
+`
+
+type CreateTaskReminderParams struct {
+	ID          pgtype.UUID        `json:"id"`
+	TaskID      pgtype.UUID        `json:"task_id"`
+	Type        string             `json:"type"`
+	Column4     interface{}        `json:"column_4"`
+	ScheduledAt pgtype.Timestamptz `json:"scheduled_at"`
+}
+
+func (q *Queries) CreateTaskReminder(ctx context.Context, arg CreateTaskReminderParams) (TaskReminder, error) {
+	row := q.db.QueryRow(ctx, createTaskReminder,
+		arg.ID,
+		arg.TaskID,
+		arg.Type,
+		arg.Column4,
+		arg.ScheduledAt,
+	)
+	var i TaskReminder
+	err := row.Scan(
+		&i.ID,
+		&i.TaskID,
+		&i.Type,
+		&i.Config,
+		&i.ScheduledAt,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const deleteTaskReminder = `-- name: DeleteTaskReminder :exec
+DELETE FROM task_reminders WHERE id = $1
+`
+
+func (q *Queries) DeleteTaskReminder(ctx context.Context, id pgtype.UUID) error {
+	_, err := q.db.Exec(ctx, deleteTaskReminder, id)
+	return err
+}
+
+const deleteTaskRemindersByTask = `-- name: DeleteTaskRemindersByTask :exec
+DELETE FROM task_reminders WHERE task_id = $1
+`
+
+func (q *Queries) DeleteTaskRemindersByTask(ctx context.Context, taskID pgtype.UUID) error {
+	_, err := q.db.Exec(ctx, deleteTaskRemindersByTask, taskID)
+	return err
+}
+
+const getTaskReminderByID = `-- name: GetTaskReminderByID :one
+SELECT id, task_id, type, config, scheduled_at, created_at FROM task_reminders
+WHERE id = $1
+`
+
+func (q *Queries) GetTaskReminderByID(ctx context.Context, id pgtype.UUID) (TaskReminder, error) {
+	row := q.db.QueryRow(ctx, getTaskReminderByID, id)
+	var i TaskReminder
+	err := row.Scan(
+		&i.ID,
+		&i.TaskID,
+		&i.Type,
+		&i.Config,
+		&i.ScheduledAt,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const listTaskReminders = `-- name: ListTaskReminders :many
+SELECT id, task_id, type, config, scheduled_at, created_at FROM task_reminders
+WHERE task_id = $1
+ORDER BY scheduled_at ASC
+`
+
+func (q *Queries) ListTaskReminders(ctx context.Context, taskID pgtype.UUID) ([]TaskReminder, error) {
+	rows, err := q.db.Query(ctx, listTaskReminders, taskID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []TaskReminder{}
+	for rows.Next() {
+		var i TaskReminder
+		if err := rows.Scan(
+			&i.ID,
+			&i.TaskID,
+			&i.Type,
+			&i.Config,
+			&i.ScheduledAt,
+			&i.CreatedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listTaskRemindersDueBefore = `-- name: ListTaskRemindersDueBefore :many
+SELECT tr.id, tr.task_id, tr.type, tr.config, tr.scheduled_at, tr.created_at, t.owner_id, t.title
+FROM task_reminders tr
+JOIN tasks t ON t.id = tr.task_id
+WHERE tr.scheduled_at <= $1
+  AND t.deleted_at IS NULL
+`
+
+type ListTaskRemindersDueBeforeRow struct {
+	ID          pgtype.UUID        `json:"id"`
+	TaskID      pgtype.UUID        `json:"task_id"`
+	Type        string             `json:"type"`
+	Config      []byte             `json:"config"`
+	ScheduledAt pgtype.Timestamptz `json:"scheduled_at"`
+	CreatedAt   pgtype.Timestamptz `json:"created_at"`
+	OwnerID     pgtype.UUID        `json:"owner_id"`
+	Title       string             `json:"title"`
+}
+
+func (q *Queries) ListTaskRemindersDueBefore(ctx context.Context, scheduledAt pgtype.Timestamptz) ([]ListTaskRemindersDueBeforeRow, error) {
+	rows, err := q.db.Query(ctx, listTaskRemindersDueBefore, scheduledAt)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []ListTaskRemindersDueBeforeRow{}
+	for rows.Next() {
+		var i ListTaskRemindersDueBeforeRow
+		if err := rows.Scan(
+			&i.ID,
+			&i.TaskID,
+			&i.Type,
+			&i.Config,
+			&i.ScheduledAt,
+			&i.CreatedAt,
+			&i.OwnerID,
+			&i.Title,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}

internal/repository/task_webhooks.sql.go

@@ -0,0 +1,117 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+// source: task_webhooks.sql
+
+package repository
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+const createTaskWebhook = `-- name: CreateTaskWebhook :one
+INSERT INTO task_webhooks (id, owner_id, url, events, secret)
+VALUES ($1, $2, $3, COALESCE($4, '[]'), $5)
+RETURNING id, owner_id, url, events, secret, created_at
+`
+
+type CreateTaskWebhookParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+	Url     string      `json:"url"`
+	Column4 interface{} `json:"column_4"`
+	Secret  pgtype.Text `json:"secret"`
+}
+
+func (q *Queries) CreateTaskWebhook(ctx context.Context, arg CreateTaskWebhookParams) (TaskWebhook, error) {
+	row := q.db.QueryRow(ctx, createTaskWebhook,
+		arg.ID,
+		arg.OwnerID,
+		arg.Url,
+		arg.Column4,
+		arg.Secret,
+	)
+	var i TaskWebhook
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Url,
+		&i.Events,
+		&i.Secret,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const deleteTaskWebhook = `-- name: DeleteTaskWebhook :exec
+DELETE FROM task_webhooks WHERE id = $1 AND owner_id = $2
+`
+
+type DeleteTaskWebhookParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) DeleteTaskWebhook(ctx context.Context, arg DeleteTaskWebhookParams) error {
+	_, err := q.db.Exec(ctx, deleteTaskWebhook, arg.ID, arg.OwnerID)
+	return err
+}
+
+const getTaskWebhookByID = `-- name: GetTaskWebhookByID :one
+SELECT id, owner_id, url, events, secret, created_at FROM task_webhooks
+WHERE id = $1 AND owner_id = $2
+`
+
+type GetTaskWebhookByIDParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) GetTaskWebhookByID(ctx context.Context, arg GetTaskWebhookByIDParams) (TaskWebhook, error) {
+	row := q.db.QueryRow(ctx, getTaskWebhookByID, arg.ID, arg.OwnerID)
+	var i TaskWebhook
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Url,
+		&i.Events,
+		&i.Secret,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const listTaskWebhooksByOwner = `-- name: ListTaskWebhooksByOwner :many
+SELECT id, owner_id, url, events, secret, created_at FROM task_webhooks
+WHERE owner_id = $1
+ORDER BY created_at DESC
+`
+
+func (q *Queries) ListTaskWebhooksByOwner(ctx context.Context, ownerID pgtype.UUID) ([]TaskWebhook, error) {
+	rows, err := q.db.Query(ctx, listTaskWebhooksByOwner, ownerID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []TaskWebhook{}
+	for rows.Next() {
+		var i TaskWebhook
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Url,
+			&i.Events,
+			&i.Secret,
+			&i.CreatedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}

internal/repository/tasks.sql.go

@@ -0,0 +1,687 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+// source: tasks.sql
+
+package repository
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+const countSubtasksByStatus = `-- name: CountSubtasksByStatus :one
+SELECT
+  COUNT(*) FILTER (WHERE status = 'done') AS done_count,
+  COUNT(*) AS total_count
+FROM tasks
+WHERE parent_id = $1 AND deleted_at IS NULL
+`
+
+type CountSubtasksByStatusRow struct {
+	DoneCount  int64 `json:"done_count"`
+	TotalCount int64 `json:"total_count"`
+}
+
+func (q *Queries) CountSubtasksByStatus(ctx context.Context, parentID pgtype.UUID) (CountSubtasksByStatusRow, error) {
+	row := q.db.QueryRow(ctx, countSubtasksByStatus, parentID)
+	var i CountSubtasksByStatusRow
+	err := row.Scan(&i.DoneCount, &i.TotalCount)
+	return i, err
+}
+
+const createTask = `-- name: CreateTask :one
+INSERT INTO tasks (id, owner_id, title, description, status, priority, due_date, project_id, parent_id, sort_order, recurrence_rule)
+VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)
+RETURNING id, owner_id, title, description, status, priority, due_date, completed_at, created_at, updated_at, deleted_at, project_id, parent_id, sort_order, recurrence_rule
+`
+
+type CreateTaskParams struct {
+	ID             pgtype.UUID        `json:"id"`
+	OwnerID        pgtype.UUID        `json:"owner_id"`
+	Title          string             `json:"title"`
+	Description    pgtype.Text        `json:"description"`
+	Status         string             `json:"status"`
+	Priority       string             `json:"priority"`
+	DueDate        pgtype.Timestamptz `json:"due_date"`
+	ProjectID      pgtype.UUID        `json:"project_id"`
+	ParentID       pgtype.UUID        `json:"parent_id"`
+	SortOrder      int32              `json:"sort_order"`
+	RecurrenceRule pgtype.Text        `json:"recurrence_rule"`
+}
+
+func (q *Queries) CreateTask(ctx context.Context, arg CreateTaskParams) (Task, error) {
+	row := q.db.QueryRow(ctx, createTask,
+		arg.ID,
+		arg.OwnerID,
+		arg.Title,
+		arg.Description,
+		arg.Status,
+		arg.Priority,
+		arg.DueDate,
+		arg.ProjectID,
+		arg.ParentID,
+		arg.SortOrder,
+		arg.RecurrenceRule,
+	)
+	var i Task
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Title,
+		&i.Description,
+		&i.Status,
+		&i.Priority,
+		&i.DueDate,
+		&i.CompletedAt,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.DeletedAt,
+		&i.ProjectID,
+		&i.ParentID,
+		&i.SortOrder,
+		&i.RecurrenceRule,
+	)
+	return i, err
+}
+
+const getTaskByID = `-- name: GetTaskByID :one
+SELECT id, owner_id, title, description, status, priority, due_date, completed_at, created_at, updated_at, deleted_at, project_id, parent_id, sort_order, recurrence_rule FROM tasks
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL
+`
+
+type GetTaskByIDParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) GetTaskByID(ctx context.Context, arg GetTaskByIDParams) (Task, error) {
+	row := q.db.QueryRow(ctx, getTaskByID, arg.ID, arg.OwnerID)
+	var i Task
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Title,
+		&i.Description,
+		&i.Status,
+		&i.Priority,
+		&i.DueDate,
+		&i.CompletedAt,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.DeletedAt,
+		&i.ProjectID,
+		&i.ParentID,
+		&i.SortOrder,
+		&i.RecurrenceRule,
+	)
+	return i, err
+}
+
+const getTaskByIDForUpdate = `-- name: GetTaskByIDForUpdate :one
+SELECT id, owner_id, title, description, status, priority, due_date, completed_at, created_at, updated_at, deleted_at, project_id, parent_id, sort_order, recurrence_rule FROM tasks
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL
+FOR UPDATE
+`
+
+type GetTaskByIDForUpdateParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) GetTaskByIDForUpdate(ctx context.Context, arg GetTaskByIDForUpdateParams) (Task, error) {
+	row := q.db.QueryRow(ctx, getTaskByIDForUpdate, arg.ID, arg.OwnerID)
+	var i Task
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Title,
+		&i.Description,
+		&i.Status,
+		&i.Priority,
+		&i.DueDate,
+		&i.CompletedAt,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.DeletedAt,
+		&i.ProjectID,
+		&i.ParentID,
+		&i.SortOrder,
+		&i.RecurrenceRule,
+	)
+	return i, err
+}
+
+const hardDeleteTask = `-- name: HardDeleteTask :exec
+DELETE FROM tasks WHERE id = $1 AND owner_id = $2
+`
+
+type HardDeleteTaskParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) HardDeleteTask(ctx context.Context, arg HardDeleteTaskParams) error {
+	_, err := q.db.Exec(ctx, hardDeleteTask, arg.ID, arg.OwnerID)
+	return err
+}
+
+const listSubtasks = `-- name: ListSubtasks :many
+SELECT id, owner_id, title, description, status, priority, due_date, completed_at, created_at, updated_at, deleted_at, project_id, parent_id, sort_order, recurrence_rule FROM tasks
+WHERE parent_id = $1 AND owner_id = $2 AND deleted_at IS NULL
+ORDER BY sort_order ASC, created_at ASC
+`
+
+type ListSubtasksParams struct {
+	ParentID pgtype.UUID `json:"parent_id"`
+	OwnerID  pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) ListSubtasks(ctx context.Context, arg ListSubtasksParams) ([]Task, error) {
+	rows, err := q.db.Query(ctx, listSubtasks, arg.ParentID, arg.OwnerID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Task{}
+	for rows.Next() {
+		var i Task
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Title,
+			&i.Description,
+			&i.Status,
+			&i.Priority,
+			&i.DueDate,
+			&i.CompletedAt,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.DeletedAt,
+			&i.ProjectID,
+			&i.ParentID,
+			&i.SortOrder,
+			&i.RecurrenceRule,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listTasks = `-- name: ListTasks :many
+SELECT t.id, t.owner_id, t.title, t.description, t.status, t.priority, t.due_date, t.completed_at, t.created_at, t.updated_at, t.deleted_at, t.project_id, t.parent_id, t.sort_order, t.recurrence_rule FROM tasks t
+WHERE t.owner_id = $1
+  AND t.deleted_at IS NULL
+  AND t.parent_id IS NULL
+  AND ($2::TEXT IS NULL OR t.status = $2::TEXT)
+  AND ($3::TEXT IS NULL OR t.priority = $3::TEXT)
+  AND ($4::UUID IS NULL OR t.project_id = $4::UUID)
+  AND ($5::TIMESTAMPTZ IS NULL OR t.due_date >= $5::TIMESTAMPTZ)
+  AND ($6::TIMESTAMPTZ IS NULL OR t.due_date <= $6::TIMESTAMPTZ)
+  AND (
+    $7::TIMESTAMPTZ IS NULL
+    OR (t.created_at, t.id) < ($7::TIMESTAMPTZ, $8::UUID)
+  )
+ORDER BY t.created_at DESC, t.id DESC
+LIMIT $9
+`
+
+type ListTasksParams struct {
+	OwnerID    pgtype.UUID        `json:"owner_id"`
+	Status     pgtype.Text        `json:"status"`
+	Priority   pgtype.Text        `json:"priority"`
+	ProjectID  pgtype.UUID        `json:"project_id"`
+	DueFrom    pgtype.Timestamptz `json:"due_from"`
+	DueTo      pgtype.Timestamptz `json:"due_to"`
+	CursorTime pgtype.Timestamptz `json:"cursor_time"`
+	CursorID   pgtype.UUID        `json:"cursor_id"`
+	Lim        int32              `json:"lim"`
+}
+
+func (q *Queries) ListTasks(ctx context.Context, arg ListTasksParams) ([]Task, error) {
+	rows, err := q.db.Query(ctx, listTasks,
+		arg.OwnerID,
+		arg.Status,
+		arg.Priority,
+		arg.ProjectID,
+		arg.DueFrom,
+		arg.DueTo,
+		arg.CursorTime,
+		arg.CursorID,
+		arg.Lim,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Task{}
+	for rows.Next() {
+		var i Task
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Title,
+			&i.Description,
+			&i.Status,
+			&i.Priority,
+			&i.DueDate,
+			&i.CompletedAt,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.DeletedAt,
+			&i.ProjectID,
+			&i.ParentID,
+			&i.SortOrder,
+			&i.RecurrenceRule,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listTasksByDueDate = `-- name: ListTasksByDueDate :many
+SELECT t.id, t.owner_id, t.title, t.description, t.status, t.priority, t.due_date, t.completed_at, t.created_at, t.updated_at, t.deleted_at, t.project_id, t.parent_id, t.sort_order, t.recurrence_rule FROM tasks t
+WHERE t.owner_id = $1
+  AND t.deleted_at IS NULL
+  AND t.parent_id IS NULL
+  AND ($2::TEXT IS NULL OR t.status = $2::TEXT)
+  AND ($3::TEXT IS NULL OR t.priority = $3::TEXT)
+  AND ($4::UUID IS NULL OR t.project_id = $4::UUID)
+  AND ($5::TIMESTAMPTZ IS NULL OR t.due_date >= $5::TIMESTAMPTZ)
+  AND ($6::TIMESTAMPTZ IS NULL OR t.due_date <= $6::TIMESTAMPTZ)
+ORDER BY COALESCE(t.due_date, '9999-12-31'::timestamptz) ASC NULLS LAST, t.id ASC
+LIMIT $7
+`
+
+type ListTasksByDueDateParams struct {
+	OwnerID   pgtype.UUID        `json:"owner_id"`
+	Status    pgtype.Text        `json:"status"`
+	Priority  pgtype.Text        `json:"priority"`
+	ProjectID pgtype.UUID        `json:"project_id"`
+	DueFrom   pgtype.Timestamptz `json:"due_from"`
+	DueTo     pgtype.Timestamptz `json:"due_to"`
+	Lim       int32              `json:"lim"`
+}
+
+func (q *Queries) ListTasksByDueDate(ctx context.Context, arg ListTasksByDueDateParams) ([]Task, error) {
+	rows, err := q.db.Query(ctx, listTasksByDueDate,
+		arg.OwnerID,
+		arg.Status,
+		arg.Priority,
+		arg.ProjectID,
+		arg.DueFrom,
+		arg.DueTo,
+		arg.Lim,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Task{}
+	for rows.Next() {
+		var i Task
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Title,
+			&i.Description,
+			&i.Status,
+			&i.Priority,
+			&i.DueDate,
+			&i.CompletedAt,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.DeletedAt,
+			&i.ProjectID,
+			&i.ParentID,
+			&i.SortOrder,
+			&i.RecurrenceRule,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listTasksByPriority = `-- name: ListTasksByPriority :many
+SELECT t.id, t.owner_id, t.title, t.description, t.status, t.priority, t.due_date, t.completed_at, t.created_at, t.updated_at, t.deleted_at, t.project_id, t.parent_id, t.sort_order, t.recurrence_rule FROM tasks t
+WHERE t.owner_id = $1
+  AND t.deleted_at IS NULL
+  AND t.parent_id IS NULL
+  AND ($2::TEXT IS NULL OR t.status = $2::TEXT)
+  AND ($3::TEXT IS NULL OR t.priority = $3::TEXT)
+  AND ($4::UUID IS NULL OR t.project_id = $4::UUID)
+  AND ($5::TIMESTAMPTZ IS NULL OR t.due_date >= $5::TIMESTAMPTZ)
+  AND ($6::TIMESTAMPTZ IS NULL OR t.due_date <= $6::TIMESTAMPTZ)
+ORDER BY CASE t.priority
+  WHEN 'critical' THEN 1
+  WHEN 'high' THEN 2
+  WHEN 'medium' THEN 3
+  WHEN 'low' THEN 4
+  ELSE 5
+END ASC, t.created_at DESC, t.id DESC
+LIMIT $7
+`
+
+type ListTasksByPriorityParams struct {
+	OwnerID   pgtype.UUID        `json:"owner_id"`
+	Status    pgtype.Text        `json:"status"`
+	Priority  pgtype.Text        `json:"priority"`
+	ProjectID pgtype.UUID        `json:"project_id"`
+	DueFrom   pgtype.Timestamptz `json:"due_from"`
+	DueTo     pgtype.Timestamptz `json:"due_to"`
+	Lim       int32              `json:"lim"`
+}
+
+func (q *Queries) ListTasksByPriority(ctx context.Context, arg ListTasksByPriorityParams) ([]Task, error) {
+	rows, err := q.db.Query(ctx, listTasksByPriority,
+		arg.OwnerID,
+		arg.Status,
+		arg.Priority,
+		arg.ProjectID,
+		arg.DueFrom,
+		arg.DueTo,
+		arg.Lim,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Task{}
+	for rows.Next() {
+		var i Task
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Title,
+			&i.Description,
+			&i.Status,
+			&i.Priority,
+			&i.DueDate,
+			&i.CompletedAt,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.DeletedAt,
+			&i.ProjectID,
+			&i.ParentID,
+			&i.SortOrder,
+			&i.RecurrenceRule,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listTasksWithRecurrence = `-- name: ListTasksWithRecurrence :many
+SELECT id, owner_id, title, description, status, priority, due_date, completed_at, created_at, updated_at, deleted_at, project_id, parent_id, sort_order, recurrence_rule FROM tasks
+WHERE owner_id = $1 AND deleted_at IS NULL
+  AND recurrence_rule IS NOT NULL
+  AND parent_id IS NULL
+`
+
+func (q *Queries) ListTasksWithRecurrence(ctx context.Context, ownerID pgtype.UUID) ([]Task, error) {
+	rows, err := q.db.Query(ctx, listTasksWithRecurrence, ownerID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Task{}
+	for rows.Next() {
+		var i Task
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Title,
+			&i.Description,
+			&i.Status,
+			&i.Priority,
+			&i.DueDate,
+			&i.CompletedAt,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.DeletedAt,
+			&i.ProjectID,
+			&i.ParentID,
+			&i.SortOrder,
+			&i.RecurrenceRule,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listTasksWithTag = `-- name: ListTasksWithTag :many
+SELECT DISTINCT t.id, t.owner_id, t.title, t.description, t.status, t.priority, t.due_date, t.completed_at, t.created_at, t.updated_at, t.deleted_at, t.project_id, t.parent_id, t.sort_order, t.recurrence_rule FROM tasks t
+JOIN task_tags tt ON tt.task_id = t.id
+WHERE t.owner_id = $1
+  AND t.deleted_at IS NULL
+  AND t.parent_id IS NULL
+  AND tt.tag_id = ANY($2)
+  AND ($3::TEXT IS NULL OR t.status = $3::TEXT)
+  AND ($4::UUID IS NULL OR t.project_id = $4::UUID)
+ORDER BY t.created_at DESC, t.id DESC
+LIMIT $5
+`
+
+type ListTasksWithTagParams struct {
+	OwnerID   pgtype.UUID `json:"owner_id"`
+	TagIds    pgtype.UUID `json:"tag_ids"`
+	Status    pgtype.Text `json:"status"`
+	ProjectID pgtype.UUID `json:"project_id"`
+	Lim       int32       `json:"lim"`
+}
+
+func (q *Queries) ListTasksWithTag(ctx context.Context, arg ListTasksWithTagParams) ([]Task, error) {
+	rows, err := q.db.Query(ctx, listTasksWithTag,
+		arg.OwnerID,
+		arg.TagIds,
+		arg.Status,
+		arg.ProjectID,
+		arg.Lim,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []Task{}
+	for rows.Next() {
+		var i Task
+		if err := rows.Scan(
+			&i.ID,
+			&i.OwnerID,
+			&i.Title,
+			&i.Description,
+			&i.Status,
+			&i.Priority,
+			&i.DueDate,
+			&i.CompletedAt,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.DeletedAt,
+			&i.ProjectID,
+			&i.ParentID,
+			&i.SortOrder,
+			&i.RecurrenceRule,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const markTaskComplete = `-- name: MarkTaskComplete :one
+UPDATE tasks
+SET status = 'done', completed_at = now(), updated_at = now()
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL
+RETURNING id, owner_id, title, description, status, priority, due_date, completed_at, created_at, updated_at, deleted_at, project_id, parent_id, sort_order, recurrence_rule
+`
+
+type MarkTaskCompleteParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) MarkTaskComplete(ctx context.Context, arg MarkTaskCompleteParams) (Task, error) {
+	row := q.db.QueryRow(ctx, markTaskComplete, arg.ID, arg.OwnerID)
+	var i Task
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Title,
+		&i.Description,
+		&i.Status,
+		&i.Priority,
+		&i.DueDate,
+		&i.CompletedAt,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.DeletedAt,
+		&i.ProjectID,
+		&i.ParentID,
+		&i.SortOrder,
+		&i.RecurrenceRule,
+	)
+	return i, err
+}
+
+const markTaskUncomplete = `-- name: MarkTaskUncomplete :one
+UPDATE tasks
+SET status = COALESCE($3, 'todo'), completed_at = NULL, updated_at = now()
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL
+RETURNING id, owner_id, title, description, status, priority, due_date, completed_at, created_at, updated_at, deleted_at, project_id, parent_id, sort_order, recurrence_rule
+`
+
+type MarkTaskUncompleteParams struct {
+	ID        pgtype.UUID `json:"id"`
+	OwnerID   pgtype.UUID `json:"owner_id"`
+	NewStatus pgtype.Text `json:"new_status"`
+}
+
+func (q *Queries) MarkTaskUncomplete(ctx context.Context, arg MarkTaskUncompleteParams) (Task, error) {
+	row := q.db.QueryRow(ctx, markTaskUncomplete, arg.ID, arg.OwnerID, arg.NewStatus)
+	var i Task
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Title,
+		&i.Description,
+		&i.Status,
+		&i.Priority,
+		&i.DueDate,
+		&i.CompletedAt,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.DeletedAt,
+		&i.ProjectID,
+		&i.ParentID,
+		&i.SortOrder,
+		&i.RecurrenceRule,
+	)
+	return i, err
+}
+
+const softDeleteTask = `-- name: SoftDeleteTask :exec
+UPDATE tasks SET deleted_at = now(), updated_at = now()
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL
+`
+
+type SoftDeleteTaskParams struct {
+	ID      pgtype.UUID `json:"id"`
+	OwnerID pgtype.UUID `json:"owner_id"`
+}
+
+func (q *Queries) SoftDeleteTask(ctx context.Context, arg SoftDeleteTaskParams) error {
+	_, err := q.db.Exec(ctx, softDeleteTask, arg.ID, arg.OwnerID)
+	return err
+}
+
+const updateTask = `-- name: UpdateTask :one
+UPDATE tasks
+SET title = COALESCE($1, title),
+    description = COALESCE($2, description),
+    status = COALESCE($3, status),
+    priority = COALESCE($4, priority),
+    due_date = $5,
+    project_id = $6,
+    sort_order = COALESCE($7, sort_order),
+    recurrence_rule = $8,
+    updated_at = now()
+WHERE id = $9 AND owner_id = $10 AND deleted_at IS NULL
+RETURNING id, owner_id, title, description, status, priority, due_date, completed_at, created_at, updated_at, deleted_at, project_id, parent_id, sort_order, recurrence_rule
+`
+
+type UpdateTaskParams struct {
+	Title          pgtype.Text        `json:"title"`
+	Description    pgtype.Text        `json:"description"`
+	Status         pgtype.Text        `json:"status"`
+	Priority       pgtype.Text        `json:"priority"`
+	DueDate        pgtype.Timestamptz `json:"due_date"`
+	ProjectID      pgtype.UUID        `json:"project_id"`
+	SortOrder      pgtype.Int4        `json:"sort_order"`
+	RecurrenceRule pgtype.Text        `json:"recurrence_rule"`
+	ID             pgtype.UUID        `json:"id"`
+	OwnerID        pgtype.UUID        `json:"owner_id"`
+}
+
+func (q *Queries) UpdateTask(ctx context.Context, arg UpdateTaskParams) (Task, error) {
+	row := q.db.QueryRow(ctx, updateTask,
+		arg.Title,
+		arg.Description,
+		arg.Status,
+		arg.Priority,
+		arg.DueDate,
+		arg.ProjectID,
+		arg.SortOrder,
+		arg.RecurrenceRule,
+		arg.ID,
+		arg.OwnerID,
+	)
+	var i Task
+	err := row.Scan(
+		&i.ID,
+		&i.OwnerID,
+		&i.Title,
+		&i.Description,
+		&i.Status,
+		&i.Priority,
+		&i.DueDate,
+		&i.CompletedAt,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.DeletedAt,
+		&i.ProjectID,
+		&i.ParentID,
+		&i.SortOrder,
+		&i.RecurrenceRule,
+	)
+	return i, err
+}

internal/scheduler/scheduler.go

@@ -15,6 +15,8 @@ import (
 
 const TypeReminder = "reminder:send"
 const TypeSubscriptionSync = "subscription:sync"
+const TypeTaskReminder = "task_reminder:send"
+const TypeRecurringTask = "recurring_task:generate"
 
 type ReminderPayload struct {
 	EventID    uuid.UUID `json:"event_id"`
@@ -54,10 +56,49 @@ func (s *Scheduler) ScheduleReminder(_ context.Context, eventID, reminderID, use
 	return nil
 }
 
+type TaskReminderPayload struct {
+	TaskReminderID uuid.UUID `json:"task_reminder_id"`
+	TaskID        uuid.UUID `json:"task_id"`
+	OwnerID       uuid.UUID `json:"owner_id"`
+}
+
+type RecurringTaskPayload struct {
+	TaskID  uuid.UUID `json:"task_id"`
+	OwnerID uuid.UUID `json:"owner_id"`
+}
+
 type SubscriptionSyncPayload struct {
 	SubscriptionID string `json:"subscription_id"`
 }
 
+func (s *Scheduler) ScheduleTaskReminder(_ context.Context, reminderID, taskID, ownerID uuid.UUID, triggerAt time.Time) error {
+	payload, err := json.Marshal(TaskReminderPayload{
+		TaskReminderID: reminderID,
+		TaskID:         taskID,
+		OwnerID:        ownerID,
+	})
+	if err != nil {
+		return fmt.Errorf("marshal task reminder payload: %w", err)
+	}
+	task := asynq.NewTask(TypeTaskReminder, payload)
+	_, err = s.client.Enqueue(task,
+		asynq.ProcessAt(triggerAt),
+		asynq.MaxRetry(3),
+		asynq.Queue("reminders"),
+	)
+	return err
+}
+
+func (s *Scheduler) EnqueueRecurringTask(ctx context.Context, taskID, ownerID uuid.UUID) error {
+	payload, err := json.Marshal(RecurringTaskPayload{TaskID: taskID, OwnerID: ownerID})
+	if err != nil {
+		return err
+	}
+	task := asynq.NewTask(TypeRecurringTask, payload)
+	_, err = s.client.Enqueue(task, asynq.MaxRetry(3), asynq.Queue("default"))
+	return err
+}
+
 func (s *Scheduler) EnqueueSubscriptionSync(ctx context.Context, subscriptionID string) error {
 	payload, err := json.Marshal(SubscriptionSyncPayload{SubscriptionID: subscriptionID})
 	if err != nil {
@@ -112,4 +153,8 @@ func (NoopScheduler) ScheduleReminder(_ context.Context, _, _, _ uuid.UUID, _ ti
 	return nil
 }
 
+func (NoopScheduler) ScheduleTaskReminder(_ context.Context, _, _, _ uuid.UUID, _ time.Time) error {
+	return nil
+}
+
 func (NoopScheduler) Close() error { return nil }

internal/scheduler/worker.go

@@ -46,6 +46,44 @@ func (w *ReminderWorker) HandleReminderTask(ctx context.Context, t *asynq.Task)
 	return nil
 }
 
+func (w *ReminderWorker) HandleTaskReminder(ctx context.Context, t *asynq.Task) error {
+	var payload TaskReminderPayload
+	if err := json.Unmarshal(t.Payload(), &payload); err != nil {
+		return fmt.Errorf("unmarshal task reminder payload: %w", err)
+	}
+	task, err := w.queries.GetTaskByID(ctx, repository.GetTaskByIDParams{
+		ID:      utils.ToPgUUID(payload.TaskID),
+		OwnerID: utils.ToPgUUID(payload.OwnerID),
+	})
+	if err != nil {
+		return fmt.Errorf("get task: %w", err)
+	}
+	if task.DeletedAt.Valid {
+		return nil
+	}
+	log.Printf("task reminder triggered: task=%s title=%s", payload.TaskID, task.Title)
+	return nil
+}
+
+func (w *ReminderWorker) HandleRecurringTask(ctx context.Context, t *asynq.Task) error {
+	var payload RecurringTaskPayload
+	if err := json.Unmarshal(t.Payload(), &payload); err != nil {
+		return fmt.Errorf("unmarshal recurring task payload: %w", err)
+	}
+	task, err := w.queries.GetTaskByID(ctx, repository.GetTaskByIDParams{
+		ID:      utils.ToPgUUID(payload.TaskID),
+		OwnerID: utils.ToPgUUID(payload.OwnerID),
+	})
+	if err != nil {
+		return nil
+	}
+	if !task.RecurrenceRule.Valid || task.RecurrenceRule.String == "" {
+		return nil
+	}
+	log.Printf("recurring task: task=%s (generation stub)", payload.TaskID)
+	return nil
+}
+
 type SubscriptionSyncWorker struct {
 	syncer SubscriptionSyncer
 }
@@ -82,6 +120,8 @@ func StartWorker(redisAddr string, worker *ReminderWorker, subSyncWorker *Subscr
 
 	mux := asynq.NewServeMux()
 	mux.HandleFunc(TypeReminder, worker.HandleReminderTask)
+	mux.HandleFunc(TypeTaskReminder, worker.HandleTaskReminder)
+	mux.HandleFunc(TypeRecurringTask, worker.HandleRecurringTask)
 	if subSyncWorker != nil {
 		mux.HandleFunc(TypeSubscriptionSync, subSyncWorker.HandleSubscriptionSync)
 	}

internal/service/project.go

@@ -0,0 +1,274 @@
+package service
+
+import (
+	"context"
+	"time"
+
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/repository"
+	"github.com/calendarapi/internal/utils"
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5"
+)
+
+type ProjectService struct {
+	queries *repository.Queries
+	audit   *AuditService
+}
+
+func NewProjectService(queries *repository.Queries, audit *AuditService) *ProjectService {
+	return &ProjectService{queries: queries, audit: audit}
+}
+
+type CreateProjectRequest struct {
+	Name     string
+	Color    *string
+	IsShared *bool
+	Deadline *time.Time
+	SortOrder *int
+}
+
+type UpdateProjectRequest struct {
+	Name     *string
+	Color    *string
+	IsShared *bool
+	Deadline *time.Time
+	SortOrder *int
+}
+
+func (s *ProjectService) Create(ctx context.Context, userID uuid.UUID, req CreateProjectRequest) (*models.Project, error) {
+	if len(req.Name) < 1 || len(req.Name) > 100 {
+		return nil, models.NewValidationError("project name must be 1-100 characters")
+	}
+	color := "#3B82F6"
+	if req.Color != nil {
+		if err := utils.ValidateColor(*req.Color); err != nil {
+			return nil, err
+		}
+		color = *req.Color
+	}
+	isShared := false
+	if req.IsShared != nil {
+		isShared = *req.IsShared
+	}
+	sortOrder := int32(0)
+	if req.SortOrder != nil {
+		sortOrder = int32(*req.SortOrder)
+	}
+
+	id := uuid.New()
+	p, err := s.queries.CreateProject(ctx, repository.CreateProjectParams{
+		ID:       utils.ToPgUUID(id),
+		OwnerID:  utils.ToPgUUID(userID),
+		Name:     req.Name,
+		Color:    color,
+		Column5:  isShared,
+		Deadline: utils.ToPgTimestamptzPtr(req.Deadline),
+		Column7:  sortOrder,
+	})
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	s.audit.Log(ctx, "project", id, "CREATE_PROJECT", userID)
+	return projectFromDB(p), nil
+}
+
+func (s *ProjectService) Get(ctx context.Context, userID uuid.UUID, projectID uuid.UUID) (*models.Project, error) {
+	p, err := s.queries.GetProjectByID(ctx, repository.GetProjectByIDParams{
+		ID:      utils.ToPgUUID(projectID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+	return projectFromDB(p), nil
+}
+
+func (s *ProjectService) List(ctx context.Context, userID uuid.UUID) ([]models.Project, error) {
+	rows, err := s.queries.ListProjectsForUser(ctx, utils.ToPgUUID(userID))
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	projects := make([]models.Project, 0, len(rows))
+	for _, r := range rows {
+		projects = append(projects, *projectFromDB(r))
+	}
+	return projects, nil
+}
+
+func (s *ProjectService) Update(ctx context.Context, userID uuid.UUID, projectID uuid.UUID, req UpdateProjectRequest) (*models.Project, error) {
+	if req.Name != nil && (len(*req.Name) < 1 || len(*req.Name) > 100) {
+		return nil, models.NewValidationError("project name must be 1-100 characters")
+	}
+	if req.Color != nil {
+		if err := utils.ValidateColor(*req.Color); err != nil {
+			return nil, err
+		}
+	}
+
+	updateParams := repository.UpdateProjectParams{
+		ID:      utils.ToPgUUID(projectID),
+		OwnerID: utils.ToPgUUID(userID),
+	}
+	if req.Name != nil {
+		updateParams.Name = utils.ToPgTextPtr(req.Name)
+	}
+	if req.Color != nil {
+		updateParams.Color = utils.ToPgTextPtr(req.Color)
+	}
+	if req.IsShared != nil {
+		updateParams.IsShared = utils.ToPgBoolPtr(req.IsShared)
+	}
+	if req.Deadline != nil {
+		updateParams.Deadline = utils.ToPgTimestamptzPtr(req.Deadline)
+	}
+	if req.SortOrder != nil {
+		updateParams.SortOrder = utils.ToPgInt4Ptr(req.SortOrder)
+	}
+
+	p, err := s.queries.UpdateProject(ctx, updateParams)
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+
+	s.audit.Log(ctx, "project", projectID, "UPDATE_PROJECT", userID)
+	return projectFromDB(p), nil
+}
+
+func (s *ProjectService) Delete(ctx context.Context, userID uuid.UUID, projectID uuid.UUID) error {
+	err := s.queries.SoftDeleteProject(ctx, repository.SoftDeleteProjectParams{
+		ID:      utils.ToPgUUID(projectID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		return models.ErrInternal
+	}
+	s.audit.Log(ctx, "project", projectID, "DELETE_PROJECT", userID)
+	return nil
+}
+
+func (s *ProjectService) Share(ctx context.Context, userID uuid.UUID, projectID uuid.UUID, targetEmail, role string) error {
+	_, err := s.queries.GetProjectByID(ctx, repository.GetProjectByIDParams{
+		ID:      utils.ToPgUUID(projectID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return models.ErrNotFound
+		}
+		return models.ErrInternal
+	}
+	if role != "editor" && role != "viewer" {
+		return models.NewValidationError("role must be editor or viewer")
+	}
+
+	targetUser, err := s.queries.GetUserByEmail(ctx, utils.NormalizeEmail(targetEmail))
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return models.NewNotFoundError("user not found")
+		}
+		return models.ErrInternal
+	}
+
+	targetID := utils.FromPgUUID(targetUser.ID)
+	if targetID == userID {
+		return models.NewValidationError("cannot share with yourself")
+	}
+
+	return s.queries.AddProjectMember(ctx, repository.AddProjectMemberParams{
+		ProjectID: utils.ToPgUUID(projectID),
+		UserID:    utils.ToPgUUID(targetID),
+		Role:      role,
+	})
+}
+
+func (s *ProjectService) AddMember(ctx context.Context, userID uuid.UUID, projectID uuid.UUID, targetUserID uuid.UUID, role string) error {
+	if role != "owner" && role != "editor" && role != "viewer" {
+		return models.NewValidationError("invalid role")
+	}
+	_, err := s.queries.GetProjectByID(ctx, repository.GetProjectByIDParams{
+		ID:      utils.ToPgUUID(projectID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return models.ErrNotFound
+		}
+		return models.ErrInternal
+	}
+	return s.queries.AddProjectMember(ctx, repository.AddProjectMemberParams{
+		ProjectID: utils.ToPgUUID(projectID),
+		UserID:    utils.ToPgUUID(targetUserID),
+		Role:      role,
+	})
+}
+
+func (s *ProjectService) RemoveMember(ctx context.Context, userID uuid.UUID, projectID uuid.UUID, targetUserID uuid.UUID) error {
+	_, err := s.queries.GetProjectByID(ctx, repository.GetProjectByIDParams{
+		ID:      utils.ToPgUUID(projectID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return models.ErrNotFound
+		}
+		return models.ErrInternal
+	}
+	return s.queries.RemoveProjectMember(ctx, repository.RemoveProjectMemberParams{
+		ProjectID: utils.ToPgUUID(projectID),
+		UserID:    utils.ToPgUUID(targetUserID),
+	})
+}
+
+func (s *ProjectService) ListMembers(ctx context.Context, userID uuid.UUID, projectID uuid.UUID) ([]models.ProjectMember, error) {
+	_, err := s.queries.GetProjectByID(ctx, repository.GetProjectByIDParams{
+		ID:      utils.ToPgUUID(projectID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+
+	rows, err := s.queries.ListProjectMembers(ctx, utils.ToPgUUID(projectID))
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	members := make([]models.ProjectMember, 0, len(rows))
+	for _, r := range rows {
+		members = append(members, models.ProjectMember{
+			UserID: utils.FromPgUUID(r.UserID),
+			Email:  r.Email,
+			Role:   r.Role,
+		})
+	}
+	return members, nil
+}
+
+func projectFromDB(p repository.Project) *models.Project {
+	proj := &models.Project{
+		ID:        utils.FromPgUUID(p.ID),
+		OwnerID:   utils.FromPgUUID(p.OwnerID),
+		Name:      p.Name,
+		Color:     p.Color,
+		IsShared:  p.IsShared,
+		SortOrder: int(p.SortOrder),
+		CreatedAt: utils.FromPgTimestamptz(p.CreatedAt),
+		UpdatedAt: utils.FromPgTimestamptz(p.UpdatedAt),
+	}
+	if p.Deadline.Valid {
+		proj.Deadline = &p.Deadline.Time
+	}
+	return proj
+}

internal/service/tag.go

@@ -0,0 +1,159 @@
+package service
+
+import (
+	"context"
+
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/repository"
+	"github.com/calendarapi/internal/utils"
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5"
+)
+
+type TagService struct {
+	queries *repository.Queries
+}
+
+func NewTagService(queries *repository.Queries) *TagService {
+	return &TagService{queries: queries}
+}
+
+type CreateTagRequest struct {
+	Name  string
+	Color *string
+}
+
+type UpdateTagRequest struct {
+	Name  *string
+	Color *string
+}
+
+func (s *TagService) Create(ctx context.Context, userID uuid.UUID, req CreateTagRequest) (*models.Tag, error) {
+	if len(req.Name) < 1 || len(req.Name) > 50 {
+		return nil, models.NewValidationError("tag name must be 1-50 characters")
+	}
+	color := "#6B7280"
+	if req.Color != nil {
+		if err := utils.ValidateColor(*req.Color); err != nil {
+			return nil, err
+		}
+		color = *req.Color
+	}
+
+	id := uuid.New()
+	t, err := s.queries.CreateTag(ctx, repository.CreateTagParams{
+		ID:      utils.ToPgUUID(id),
+		OwnerID: utils.ToPgUUID(userID),
+		Name:    req.Name,
+		Column4: color,
+	})
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	tag := tagFromDB(t)
+	return &tag, nil
+}
+
+func (s *TagService) Get(ctx context.Context, userID uuid.UUID, tagID uuid.UUID) (*models.Tag, error) {
+	t, err := s.queries.GetTagByID(ctx, repository.GetTagByIDParams{
+		ID:      utils.ToPgUUID(tagID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+	tag := tagFromDB(t)
+	return &tag, nil
+}
+
+func (s *TagService) List(ctx context.Context, userID uuid.UUID) ([]models.Tag, error) {
+	rows, err := s.queries.ListTagsByOwner(ctx, utils.ToPgUUID(userID))
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	tags := make([]models.Tag, 0, len(rows))
+	for _, r := range rows {
+		tags = append(tags, tagFromDB(r))
+	}
+	return tags, nil
+}
+
+func (s *TagService) Update(ctx context.Context, userID uuid.UUID, tagID uuid.UUID, req UpdateTagRequest) (*models.Tag, error) {
+	if req.Name != nil && (len(*req.Name) < 1 || len(*req.Name) > 50) {
+		return nil, models.NewValidationError("tag name must be 1-50 characters")
+	}
+	if req.Color != nil {
+		if err := utils.ValidateColor(*req.Color); err != nil {
+			return nil, err
+		}
+	}
+
+	updateParams := repository.UpdateTagParams{
+		ID:      utils.ToPgUUID(tagID),
+		OwnerID: utils.ToPgUUID(userID),
+	}
+	if req.Name != nil {
+		updateParams.Name = utils.ToPgTextPtr(req.Name)
+	}
+	if req.Color != nil {
+		updateParams.Color = utils.ToPgTextPtr(req.Color)
+	}
+
+	t, err := s.queries.UpdateTag(ctx, updateParams)
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+	tag := tagFromDB(t)
+	return &tag, nil
+}
+
+func (s *TagService) Delete(ctx context.Context, userID uuid.UUID, tagID uuid.UUID) error {
+	err := s.queries.DeleteTag(ctx, repository.DeleteTagParams{
+		ID:      utils.ToPgUUID(tagID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		return models.ErrInternal
+	}
+	return nil
+}
+
+func (s *TagService) AttachToTask(ctx context.Context, userID uuid.UUID, tagID uuid.UUID, taskID uuid.UUID) error {
+	if _, err := s.queries.GetTagByID(ctx, repository.GetTagByIDParams{
+		ID:      utils.ToPgUUID(tagID),
+		OwnerID: utils.ToPgUUID(userID),
+	}); err != nil {
+		if err == pgx.ErrNoRows {
+			return models.ErrNotFound
+		}
+		return models.ErrInternal
+	}
+	return s.queries.AttachTagToTask(ctx, repository.AttachTagToTaskParams{
+		TaskID: utils.ToPgUUID(taskID),
+		TagID:  utils.ToPgUUID(tagID),
+	})
+}
+
+func (s *TagService) DetachFromTask(ctx context.Context, userID uuid.UUID, tagID uuid.UUID, taskID uuid.UUID) error {
+	if _, err := s.queries.GetTagByID(ctx, repository.GetTagByIDParams{
+		ID:      utils.ToPgUUID(tagID),
+		OwnerID: utils.ToPgUUID(userID),
+	}); err != nil {
+		if err == pgx.ErrNoRows {
+			return models.ErrNotFound
+		}
+		return models.ErrInternal
+	}
+	return s.queries.DetachTagFromTask(ctx, repository.DetachTagFromTaskParams{
+		TaskID: utils.ToPgUUID(taskID),
+		TagID:  utils.ToPgUUID(tagID),
+	})
+}

internal/service/task.go

@@ -0,0 +1,436 @@
+package service
+
+import (
+	"context"
+	"time"
+
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/repository"
+	"github.com/calendarapi/internal/utils"
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+type TaskService struct {
+	queries *repository.Queries
+	audit   *AuditService
+	webhook *TaskWebhookService
+}
+
+func NewTaskService(queries *repository.Queries, audit *AuditService, webhook *TaskWebhookService) *TaskService {
+	return &TaskService{queries: queries, audit: audit, webhook: webhook}
+}
+
+type CreateTaskRequest struct {
+	Title          string
+	Description    *string
+	Status         *string
+	Priority       *string
+	DueDate        *time.Time
+	ProjectID      *uuid.UUID
+	ParentID       *uuid.UUID
+	SortOrder      *int
+	RecurrenceRule *string
+}
+
+type UpdateTaskRequest struct {
+	Title          *string
+	Description    *string
+	Status         *string
+	Priority       *string
+	DueDate        *time.Time
+	ProjectID      *uuid.UUID
+	SortOrder      *int
+	RecurrenceRule *string
+}
+
+type ListTasksParams struct {
+	Status    *string
+	Priority  *string
+	DueFrom   *time.Time
+	DueTo     *time.Time
+	ProjectID *uuid.UUID
+	TagIDs    []uuid.UUID
+	Sort      string // created_at, due_date, priority
+	Order     string // asc, desc
+	Limit     int
+	Cursor    string
+}
+
+func (s *TaskService) Create(ctx context.Context, userID uuid.UUID, req CreateTaskRequest) (*models.Task, error) {
+	if err := utils.ValidateTaskTitle(req.Title); err != nil {
+		return nil, err
+	}
+	status := "todo"
+	if req.Status != nil {
+		if err := utils.ValidateTaskStatus(*req.Status); err != nil {
+			return nil, err
+		}
+		status = *req.Status
+	}
+	priority := "medium"
+	if req.Priority != nil {
+		if err := utils.ValidateTaskPriority(*req.Priority); err != nil {
+			return nil, err
+		}
+		priority = *req.Priority
+	}
+	sortOrder := int32(0)
+	if req.SortOrder != nil {
+		sortOrder = int32(*req.SortOrder)
+	}
+
+	id := uuid.New()
+	t, err := s.queries.CreateTask(ctx, repository.CreateTaskParams{
+		ID:             utils.ToPgUUID(id),
+		OwnerID:        utils.ToPgUUID(userID),
+		Title:          req.Title,
+		Description:    utils.ToPgTextPtr(req.Description),
+		Status:         status,
+		Priority:       priority,
+		DueDate:        utils.ToPgTimestamptzPtr(req.DueDate),
+		ProjectID:      utils.ToPgUUIDPtr(req.ProjectID),
+		ParentID:       utils.ToPgUUIDPtr(req.ParentID),
+		SortOrder:      sortOrder,
+		RecurrenceRule: utils.ToPgTextPtr(req.RecurrenceRule),
+	})
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	s.audit.Log(ctx, "task", id, "CREATE_TASK", userID)
+	task := taskFromDB(t)
+
+	if s.webhook != nil {
+		go s.webhook.Deliver(ctx, userID, "created", task)
+	}
+
+	return task, nil
+}
+
+func (s *TaskService) Get(ctx context.Context, userID uuid.UUID, taskID uuid.UUID) (*models.Task, error) {
+	t, err := s.queries.GetTaskByID(ctx, repository.GetTaskByIDParams{
+		ID:      utils.ToPgUUID(taskID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+	task := taskFromDB(t)
+
+	tags, _ := s.queries.ListTagsByTask(ctx, utils.ToPgUUID(taskID))
+	task.Tags = make([]models.Tag, 0, len(tags))
+	for _, tag := range tags {
+		task.Tags = append(task.Tags, tagFromDB(tag))
+	}
+
+	if count, err := s.queries.CountSubtasksByStatus(ctx, utils.ToPgUUID(taskID)); err == nil && count.TotalCount > 0 {
+		pct := int(100 * count.DoneCount / count.TotalCount)
+		task.CompletionPercentage = &pct
+	}
+
+	return task, nil
+}
+
+func (s *TaskService) List(ctx context.Context, userID uuid.UUID, params ListTasksParams) ([]models.Task, *string, error) {
+	lim := utils.ClampLimit(params.Limit)
+	if lim <= 0 {
+		lim = 50
+	}
+
+	var status, priority pgtype.Text
+	if params.Status != nil && *params.Status != "" {
+		status = utils.ToPgText(*params.Status)
+	}
+	if params.Priority != nil && *params.Priority != "" {
+		priority = utils.ToPgText(*params.Priority)
+	}
+	projectID := utils.ToPgUUIDPtr(params.ProjectID)
+	dueFrom := utils.ToPgTimestamptzPtr(params.DueFrom)
+	dueTo := utils.ToPgTimestamptzPtr(params.DueTo)
+
+	var cursorTime *time.Time
+	var cursorID *uuid.UUID
+	if params.Cursor != "" {
+		ct, cid, err := utils.ParseCursor(params.Cursor)
+		if err != nil {
+			return nil, nil, models.NewValidationError("invalid cursor")
+		}
+		cursorTime = ct
+		cursorID = cid
+	}
+
+	listParams := repository.ListTasksParams{
+		OwnerID:   utils.ToPgUUID(userID),
+		Status:    status,
+		Priority:  priority,
+		ProjectID: projectID,
+		DueFrom:   dueFrom,
+		DueTo:     dueTo,
+		Lim:       lim + 1,
+	}
+	if cursorTime != nil && cursorID != nil {
+		listParams.CursorTime = utils.ToPgTimestamptz(*cursorTime)
+		listParams.CursorID = utils.ToPgUUID(*cursorID)
+	}
+
+	rows, err := s.queries.ListTasks(ctx, listParams)
+	if err != nil {
+		return nil, nil, models.ErrInternal
+	}
+
+	tasks := make([]models.Task, 0, len(rows))
+	for _, r := range rows {
+		tasks = append(tasks, *taskFromDB(r))
+	}
+
+	var nextCursor *string
+	if len(tasks) > int(lim) {
+		tasks = tasks[:lim]
+		last := tasks[len(tasks)-1]
+		c := utils.EncodeCursor(last.CreatedAt, last.ID)
+		nextCursor = &c
+	}
+
+	return tasks, nextCursor, nil
+}
+
+func (s *TaskService) Update(ctx context.Context, userID uuid.UUID, taskID uuid.UUID, req UpdateTaskRequest) (*models.Task, error) {
+	if req.Title != nil {
+		if err := utils.ValidateTaskTitle(*req.Title); err != nil {
+			return nil, err
+		}
+	}
+	if req.Status != nil {
+		if err := utils.ValidateTaskStatus(*req.Status); err != nil {
+			return nil, err
+		}
+	}
+	if req.Priority != nil {
+		if err := utils.ValidateTaskPriority(*req.Priority); err != nil {
+			return nil, err
+		}
+	}
+
+	prev, err := s.queries.GetTaskByID(ctx, repository.GetTaskByIDParams{
+		ID:      utils.ToPgUUID(taskID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+
+	updateParams := repository.UpdateTaskParams{
+		ID:      utils.ToPgUUID(taskID),
+		OwnerID: utils.ToPgUUID(userID),
+	}
+	if req.Title != nil {
+		updateParams.Title = utils.ToPgTextPtr(req.Title)
+	}
+	if req.Description != nil {
+		updateParams.Description = utils.ToPgTextPtr(req.Description)
+	}
+	if req.Status != nil {
+		updateParams.Status = utils.ToPgTextPtr(req.Status)
+	}
+	if req.Priority != nil {
+		updateParams.Priority = utils.ToPgTextPtr(req.Priority)
+	}
+	if req.DueDate != nil {
+		updateParams.DueDate = utils.ToPgTimestamptzPtr(req.DueDate)
+	}
+	if req.ProjectID != nil {
+		updateParams.ProjectID = utils.ToPgUUIDPtr(req.ProjectID)
+	}
+	if req.SortOrder != nil {
+		updateParams.SortOrder = utils.ToPgInt4Ptr(req.SortOrder)
+	}
+	if req.RecurrenceRule != nil {
+		updateParams.RecurrenceRule = utils.ToPgTextPtr(req.RecurrenceRule)
+	}
+
+	t, err := s.queries.UpdateTask(ctx, updateParams)
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+
+	task := taskFromDB(t)
+	s.audit.Log(ctx, "task", taskID, "UPDATE_TASK", userID)
+
+	if s.webhook != nil && req.Status != nil && *req.Status != prev.Status {
+		go s.webhook.Deliver(ctx, userID, "status_change", task)
+		if *req.Status == "done" {
+			go s.webhook.Deliver(ctx, userID, "completion", task)
+		}
+	}
+
+	if prev.ParentID.Valid {
+		s.maybeAutoCompleteParent(ctx, userID, utils.FromPgUUID(prev.ParentID))
+	}
+
+	return task, nil
+}
+
+func (s *TaskService) Delete(ctx context.Context, userID uuid.UUID, taskID uuid.UUID, permanent bool) error {
+	if permanent {
+		err := s.queries.HardDeleteTask(ctx, repository.HardDeleteTaskParams{
+			ID:      utils.ToPgUUID(taskID),
+			OwnerID: utils.ToPgUUID(userID),
+		})
+		if err != nil {
+			return models.ErrInternal
+		}
+	} else {
+		err := s.queries.SoftDeleteTask(ctx, repository.SoftDeleteTaskParams{
+			ID:      utils.ToPgUUID(taskID),
+			OwnerID: utils.ToPgUUID(userID),
+		})
+		if err != nil {
+			return models.ErrInternal
+		}
+	}
+	s.audit.Log(ctx, "task", taskID, "DELETE_TASK", userID)
+	return nil
+}
+
+func (s *TaskService) MarkComplete(ctx context.Context, userID uuid.UUID, taskID uuid.UUID) (*models.Task, error) {
+	blockers, _ := s.queries.ListTaskBlockers(ctx, utils.ToPgUUID(taskID))
+	for _, b := range blockers {
+		if b.Status != "done" {
+			return nil, models.NewConflictError("cannot complete: blocked by incomplete task")
+		}
+	}
+
+	t, err := s.queries.MarkTaskComplete(ctx, repository.MarkTaskCompleteParams{
+		ID:      utils.ToPgUUID(taskID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+
+	task := taskFromDB(t)
+	s.audit.Log(ctx, "task", taskID, "COMPLETE_TASK", userID)
+	if s.webhook != nil {
+		go s.webhook.Deliver(ctx, userID, "completion", task)
+	}
+
+	if t.ParentID.Valid {
+		s.maybeAutoCompleteParent(ctx, userID, utils.FromPgUUID(t.ParentID))
+	}
+
+	return task, nil
+}
+
+func (s *TaskService) MarkUncomplete(ctx context.Context, userID uuid.UUID, taskID uuid.UUID, newStatus *string) (*models.Task, error) {
+	status := "todo"
+	if newStatus != nil {
+		if err := utils.ValidateTaskStatus(*newStatus); err != nil {
+			return nil, err
+		}
+		status = *newStatus
+	}
+
+	t, err := s.queries.MarkTaskUncomplete(ctx, repository.MarkTaskUncompleteParams{
+		ID:        utils.ToPgUUID(taskID),
+		OwnerID:   utils.ToPgUUID(userID),
+		NewStatus: utils.ToPgTextPtr(&status),
+	})
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+
+	task := taskFromDB(t)
+	s.audit.Log(ctx, "task", taskID, "UNCOMPLETE_TASK", userID)
+	return task, nil
+}
+
+func (s *TaskService) ListSubtasks(ctx context.Context, userID uuid.UUID, taskID uuid.UUID) ([]models.Task, error) {
+	rows, err := s.queries.ListSubtasks(ctx, repository.ListSubtasksParams{
+		ParentID: utils.ToPgUUID(taskID),
+		OwnerID:  utils.ToPgUUID(userID),
+	})
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	tasks := make([]models.Task, 0, len(rows))
+	for _, r := range rows {
+		tasks = append(tasks, *taskFromDB(r))
+	}
+	return tasks, nil
+}
+
+func (s *TaskService) maybeAutoCompleteParent(ctx context.Context, userID uuid.UUID, parentID uuid.UUID) {
+	count, err := s.queries.CountSubtasksByStatus(ctx, utils.ToPgUUID(parentID))
+	if err != nil || count.TotalCount == 0 {
+		return
+	}
+	if count.DoneCount == count.TotalCount {
+		_, _ = s.queries.MarkTaskComplete(ctx, repository.MarkTaskCompleteParams{
+			ID:      utils.ToPgUUID(parentID),
+			OwnerID: utils.ToPgUUID(userID),
+		})
+		s.audit.Log(ctx, "task", parentID, "AUTO_COMPLETE_PARENT", userID)
+	}
+}
+
+func taskFromDB(t repository.Task) *models.Task {
+	task := &models.Task{
+		ID:        utils.FromPgUUID(t.ID),
+		OwnerID:   utils.FromPgUUID(t.OwnerID),
+		Title:     t.Title,
+		Status:    t.Status,
+		Priority:  t.Priority,
+		CreatedAt: utils.FromPgTimestamptz(t.CreatedAt),
+		UpdatedAt: utils.FromPgTimestamptz(t.UpdatedAt),
+		SortOrder: int(t.SortOrder),
+	}
+	if t.Description.Valid {
+		task.Description = &t.Description.String
+	}
+	if t.DueDate.Valid {
+		task.DueDate = &t.DueDate.Time
+	}
+	if t.CompletedAt.Valid {
+		task.CompletedAt = &t.CompletedAt.Time
+	}
+	if t.ProjectID.Valid {
+		id := utils.FromPgUUID(t.ProjectID)
+		task.ProjectID = &id
+	}
+	if t.ParentID.Valid {
+		id := utils.FromPgUUID(t.ParentID)
+		task.ParentID = &id
+	}
+	if t.RecurrenceRule.Valid {
+		task.RecurrenceRule = &t.RecurrenceRule.String
+	}
+	return task
+}
+
+func tagFromDB(t repository.Tag) models.Tag {
+	return models.Tag{
+		ID:        utils.FromPgUUID(t.ID),
+		OwnerID:   utils.FromPgUUID(t.OwnerID),
+		Name:      t.Name,
+		Color:     t.Color,
+		CreatedAt: utils.FromPgTimestamptz(t.CreatedAt),
+	}
+}

internal/service/task_dependency.go

@@ -0,0 +1,91 @@
+package service
+
+import (
+	"context"
+
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/repository"
+	"github.com/calendarapi/internal/utils"
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5"
+)
+
+type TaskDependencyService struct {
+	queries *repository.Queries
+}
+
+func NewTaskDependencyService(queries *repository.Queries) *TaskDependencyService {
+	return &TaskDependencyService{queries: queries}
+}
+
+func (s *TaskDependencyService) Add(ctx context.Context, userID uuid.UUID, taskID uuid.UUID, blocksTaskID uuid.UUID) error {
+	if taskID == blocksTaskID {
+		return models.NewValidationError("task cannot depend on itself")
+	}
+
+	if _, err := s.queries.GetTaskByID(ctx, repository.GetTaskByIDParams{
+		ID:      utils.ToPgUUID(taskID),
+		OwnerID: utils.ToPgUUID(userID),
+	}); err != nil {
+		if err == pgx.ErrNoRows {
+			return models.ErrNotFound
+		}
+		return models.ErrInternal
+	}
+
+	hasCircle, err := s.queries.CheckDirectCircularDependency(ctx, repository.CheckDirectCircularDependencyParams{
+		BlocksTaskID: utils.ToPgUUID(taskID),
+		TaskID:       utils.ToPgUUID(blocksTaskID),
+	})
+	if err != nil {
+		return models.ErrInternal
+	}
+	if hasCircle {
+		return models.NewConflictError("circular dependency detected")
+	}
+
+	return s.queries.AddTaskDependency(ctx, repository.AddTaskDependencyParams{
+		TaskID:       utils.ToPgUUID(taskID),
+		BlocksTaskID: utils.ToPgUUID(blocksTaskID),
+	})
+}
+
+func (s *TaskDependencyService) Remove(ctx context.Context, userID uuid.UUID, taskID uuid.UUID, blocksTaskID uuid.UUID) error {
+	if _, err := s.queries.GetTaskByID(ctx, repository.GetTaskByIDParams{
+		ID:      utils.ToPgUUID(taskID),
+		OwnerID: utils.ToPgUUID(userID),
+	}); err != nil {
+		if err == pgx.ErrNoRows {
+			return models.ErrNotFound
+		}
+		return models.ErrInternal
+	}
+
+	return s.queries.RemoveTaskDependency(ctx, repository.RemoveTaskDependencyParams{
+		TaskID:       utils.ToPgUUID(taskID),
+		BlocksTaskID: utils.ToPgUUID(blocksTaskID),
+	})
+}
+
+func (s *TaskDependencyService) ListBlockers(ctx context.Context, userID uuid.UUID, taskID uuid.UUID) ([]models.Task, error) {
+	if _, err := s.queries.GetTaskByID(ctx, repository.GetTaskByIDParams{
+		ID:      utils.ToPgUUID(taskID),
+		OwnerID: utils.ToPgUUID(userID),
+	}); err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+
+	rows, err := s.queries.ListTaskBlockers(ctx, utils.ToPgUUID(taskID))
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	tasks := make([]models.Task, 0, len(rows))
+	for _, r := range rows {
+		tasks = append(tasks, *taskFromDB(r))
+	}
+	return tasks, nil
+}

internal/service/task_reminder.go

@@ -0,0 +1,123 @@
+package service
+
+import (
+	"context"
+	"encoding/json"
+	"time"
+
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/repository"
+	"github.com/calendarapi/internal/utils"
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5"
+)
+
+type TaskReminderScheduler interface {
+	ScheduleTaskReminder(ctx context.Context, reminderID, taskID, ownerID uuid.UUID, triggerAt time.Time) error
+}
+
+type TaskReminderService struct {
+	queries   *repository.Queries
+	scheduler TaskReminderScheduler
+}
+
+func NewTaskReminderService(queries *repository.Queries, scheduler TaskReminderScheduler) *TaskReminderService {
+	return &TaskReminderService{queries: queries, scheduler: scheduler}
+}
+
+type CreateTaskReminderRequest struct {
+	Type        string
+	Config      map[string]interface{}
+	ScheduledAt time.Time
+}
+
+func (s *TaskReminderService) Create(ctx context.Context, userID uuid.UUID, taskID uuid.UUID, req CreateTaskReminderRequest) (*models.TaskReminder, error) {
+	if _, err := s.queries.GetTaskByID(ctx, repository.GetTaskByIDParams{
+		ID:      utils.ToPgUUID(taskID),
+		OwnerID: utils.ToPgUUID(userID),
+	}); err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+
+	validTypes := map[string]bool{"push": true, "email": true, "webhook": true, "telegram": true, "nostr": true}
+	if !validTypes[req.Type] {
+		return nil, models.NewValidationError("invalid reminder type")
+	}
+
+	configJSON := []byte("{}")
+	if req.Config != nil {
+		configJSON, _ = json.Marshal(req.Config)
+	}
+
+	id := uuid.New()
+	rem, err := s.queries.CreateTaskReminder(ctx, repository.CreateTaskReminderParams{
+		ID:          utils.ToPgUUID(id),
+		TaskID:      utils.ToPgUUID(taskID),
+		Type:        req.Type,
+		Column4:     configJSON,
+		ScheduledAt: utils.ToPgTimestamptz(req.ScheduledAt),
+	})
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	if s.scheduler != nil {
+		_ = s.scheduler.ScheduleTaskReminder(ctx, id, taskID, userID, req.ScheduledAt)
+	}
+
+	return taskReminderFromDB(rem), nil
+}
+
+func (s *TaskReminderService) List(ctx context.Context, userID uuid.UUID, taskID uuid.UUID) ([]models.TaskReminder, error) {
+	if _, err := s.queries.GetTaskByID(ctx, repository.GetTaskByIDParams{
+		ID:      utils.ToPgUUID(taskID),
+		OwnerID: utils.ToPgUUID(userID),
+	}); err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, models.ErrNotFound
+		}
+		return nil, models.ErrInternal
+	}
+
+	rows, err := s.queries.ListTaskReminders(ctx, utils.ToPgUUID(taskID))
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	reminders := make([]models.TaskReminder, 0, len(rows))
+	for _, r := range rows {
+		reminders = append(reminders, *taskReminderFromDB(r))
+	}
+	return reminders, nil
+}
+
+func (s *TaskReminderService) Delete(ctx context.Context, userID uuid.UUID, taskID uuid.UUID, reminderID uuid.UUID) error {
+	if _, err := s.queries.GetTaskByID(ctx, repository.GetTaskByIDParams{
+		ID:      utils.ToPgUUID(taskID),
+		OwnerID: utils.ToPgUUID(userID),
+	}); err != nil {
+		if err == pgx.ErrNoRows {
+			return models.ErrNotFound
+		}
+		return models.ErrInternal
+	}
+
+	return s.queries.DeleteTaskReminder(ctx, utils.ToPgUUID(reminderID))
+}
+
+func taskReminderFromDB(r repository.TaskReminder) *models.TaskReminder {
+	rem := &models.TaskReminder{
+		ID:          utils.FromPgUUID(r.ID),
+		TaskID:      utils.FromPgUUID(r.TaskID),
+		Type:        r.Type,
+		ScheduledAt: utils.FromPgTimestamptz(r.ScheduledAt),
+		CreatedAt:   utils.FromPgTimestamptz(r.CreatedAt),
+	}
+	if len(r.Config) > 0 {
+		json.Unmarshal(r.Config, &rem.Config)
+	}
+	return rem
+}

internal/service/task_webhook.go

@@ -0,0 +1,73 @@
+package service
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"time"
+
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/repository"
+	"github.com/calendarapi/internal/utils"
+	"github.com/google/uuid"
+)
+
+type TaskWebhookService struct {
+	queries *repository.Queries
+}
+
+func NewTaskWebhookService(queries *repository.Queries) *TaskWebhookService {
+	return &TaskWebhookService{queries: queries}
+}
+
+func (s *TaskWebhookService) Deliver(ctx context.Context, ownerID uuid.UUID, event string, task *models.Task) {
+	webhooks, err := s.queries.ListTaskWebhooksByOwner(ctx, utils.ToPgUUID(ownerID))
+	if err != nil {
+		return
+	}
+
+	payload := map[string]interface{}{
+		"event":    event,
+		"task":     task,
+		"timestamp": time.Now().UTC().Format(time.RFC3339),
+	}
+	body, _ := json.Marshal(payload)
+
+	for _, wh := range webhooks {
+		if !s.webhookSubscribedTo(wh.Events, event) {
+			continue
+		}
+		secret := ""
+		if wh.Secret.Valid {
+			secret = wh.Secret.String
+		}
+		go s.postWebhook(wh.Url, body, []byte(secret))
+	}
+}
+
+func (s *TaskWebhookService) webhookSubscribedTo(eventsJSON []byte, event string) bool {
+	var events []string
+	if err := json.Unmarshal(eventsJSON, &events); err != nil {
+		return false
+	}
+	for _, e := range events {
+		if e == event {
+			return true
+		}
+	}
+	return false
+}
+
+func (s *TaskWebhookService) postWebhook(url string, body []byte, secret []byte) {
+	req, err := http.NewRequest("POST", url, bytes.NewReader(body))
+	if err != nil {
+		return
+	}
+	req.Header.Set("Content-Type", "application/json")
+	if len(secret) > 0 {
+		req.Header.Set("X-Webhook-Signature", string(secret))
+	}
+	client := &http.Client{Timeout: 10 * time.Second}
+	_, _ = client.Do(req)
+}

internal/service/task_webhook_svc.go

@@ -0,0 +1,78 @@
+package service
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/calendarapi/internal/models"
+	"github.com/calendarapi/internal/repository"
+	"github.com/calendarapi/internal/utils"
+	"github.com/google/uuid"
+)
+
+type TaskWebhookCreateRequest struct {
+	URL    string
+	Events []string
+	Secret *string
+}
+
+func (s *TaskWebhookService) Create(ctx context.Context, userID uuid.UUID, req TaskWebhookCreateRequest) (*models.TaskWebhook, error) {
+	if req.URL == "" {
+		return nil, models.NewValidationError("url is required")
+	}
+
+	eventsJSON, _ := json.Marshal(req.Events)
+	if req.Events == nil {
+		eventsJSON = []byte("[]")
+	}
+
+	id := uuid.New()
+	wh, err := s.queries.CreateTaskWebhook(ctx, repository.CreateTaskWebhookParams{
+		ID:      utils.ToPgUUID(id),
+		OwnerID: utils.ToPgUUID(userID),
+		Url:     req.URL,
+		Column4: eventsJSON,
+		Secret:  utils.ToPgTextPtr(req.Secret),
+	})
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	return taskWebhookFromDB(wh), nil
+}
+
+func (s *TaskWebhookService) List(ctx context.Context, userID uuid.UUID) ([]models.TaskWebhook, error) {
+	rows, err := s.queries.ListTaskWebhooksByOwner(ctx, utils.ToPgUUID(userID))
+	if err != nil {
+		return nil, models.ErrInternal
+	}
+
+	webhooks := make([]models.TaskWebhook, 0, len(rows))
+	for _, r := range rows {
+		webhooks = append(webhooks, *taskWebhookFromDB(r))
+	}
+	return webhooks, nil
+}
+
+func (s *TaskWebhookService) Delete(ctx context.Context, userID uuid.UUID, webhookID uuid.UUID) error {
+	return s.queries.DeleteTaskWebhook(ctx, repository.DeleteTaskWebhookParams{
+		ID:      utils.ToPgUUID(webhookID),
+		OwnerID: utils.ToPgUUID(userID),
+	})
+}
+
+func taskWebhookFromDB(wh repository.TaskWebhook) *models.TaskWebhook {
+	w := &models.TaskWebhook{
+		ID:        utils.FromPgUUID(wh.ID),
+		OwnerID:   utils.FromPgUUID(wh.OwnerID),
+		URL:       wh.Url,
+		CreatedAt: utils.FromPgTimestamptz(wh.CreatedAt),
+	}
+	if len(wh.Events) > 0 {
+		json.Unmarshal(wh.Events, &w.Events)
+	}
+	if wh.Secret.Valid {
+		w.Secret = &wh.Secret.String
+	}
+	return w
+}

internal/utils/pgtype.go

@@ -100,6 +100,13 @@ func NullPgUUID() pgtype.UUID {
 	return pgtype.UUID{Valid: false}
 }
 
+func ToPgUUIDPtr(id *uuid.UUID) pgtype.UUID {
+	if id == nil {
+		return pgtype.UUID{Valid: false}
+	}
+	return pgtype.UUID{Bytes: *id, Valid: true}
+}
+
 func NullPgTimestamptz() pgtype.Timestamptz {
 	return pgtype.Timestamptz{Valid: false}
 }

internal/utils/validation.go

@@ -95,3 +95,37 @@ func ValidateRecurrenceRangeLimit(start, end time.Time) error {
 	}
 	return nil
 }
+
+func ValidateTaskTitle(title string) error {
+	if len(title) < 1 || len(title) > 500 {
+		return models.NewValidationError("task title must be 1-500 characters")
+	}
+	return nil
+}
+
+func ValidateTaskStatus(status string) error {
+	valid := map[string]bool{"todo": true, "in_progress": true, "done": true, "archived": true}
+	if !valid[status] {
+		return models.NewValidationError("invalid task status")
+	}
+	return nil
+}
+
+func ParseTime(s string) (time.Time, error) {
+	t, err := time.Parse(time.RFC3339, s)
+	if err != nil {
+		t, err = time.Parse("2006-01-02T15:04:05Z07:00", s)
+	}
+	if err != nil {
+		t, err = time.Parse("2006-01-02", s)
+	}
+	return t, err
+}
+
+func ValidateTaskPriority(priority string) error {
+	valid := map[string]bool{"low": true, "medium": true, "high": true, "critical": true}
+	if !valid[priority] {
+		return models.NewValidationError("invalid task priority")
+	}
+	return nil
+}

migrations/000007_tasks.down.sql

@@ -0,0 +1,10 @@
+-- To-do list support rollback
+
+DROP TABLE IF EXISTS task_webhooks;
+DROP TABLE IF EXISTS task_reminders;
+DROP TABLE IF EXISTS task_dependencies;
+DROP TABLE IF EXISTS task_tags;
+DROP TABLE IF EXISTS tasks;
+DROP TABLE IF EXISTS tags;
+DROP TABLE IF EXISTS project_members;
+DROP TABLE IF EXISTS projects;

migrations/000007_tasks.up.sql

@@ -0,0 +1,111 @@
+-- To-do list support: projects, tags, tasks, and related tables
+
+-- Projects (Layer 2)
+CREATE TABLE projects (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    owner_id UUID NOT NULL REFERENCES users(id),
+    name TEXT NOT NULL,
+    color TEXT NOT NULL DEFAULT '#3B82F6',
+    is_shared BOOLEAN NOT NULL DEFAULT false,
+    deadline TIMESTAMPTZ,
+    sort_order INTEGER NOT NULL DEFAULT 0,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    deleted_at TIMESTAMPTZ
+);
+
+CREATE INDEX idx_projects_owner_id ON projects (owner_id);
+
+-- Project Members (Layer 2 shared projects)
+CREATE TABLE project_members (
+    project_id UUID NOT NULL REFERENCES projects(id),
+    user_id UUID NOT NULL REFERENCES users(id),
+    role TEXT NOT NULL CHECK (role IN ('owner', 'editor', 'viewer')),
+    PRIMARY KEY (project_id, user_id)
+);
+
+CREATE INDEX idx_project_members_project_id ON project_members (project_id);
+
+-- Tags (Layer 2)
+CREATE TABLE tags (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    owner_id UUID NOT NULL REFERENCES users(id),
+    name TEXT NOT NULL,
+    color TEXT NOT NULL DEFAULT '#6B7280',
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX idx_tags_owner_id ON tags (owner_id);
+
+-- Tasks (Layer 1 core)
+CREATE TABLE tasks (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    owner_id UUID NOT NULL REFERENCES users(id),
+    title TEXT NOT NULL,
+    description TEXT,
+    status TEXT NOT NULL DEFAULT 'todo' CHECK (status IN ('todo', 'in_progress', 'done', 'archived')),
+    priority TEXT NOT NULL DEFAULT 'medium' CHECK (priority IN ('low', 'medium', 'high', 'critical')),
+    due_date TIMESTAMPTZ,
+    completed_at TIMESTAMPTZ,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    deleted_at TIMESTAMPTZ,
+    project_id UUID REFERENCES projects(id),
+    parent_id UUID REFERENCES tasks(id),
+    sort_order INTEGER NOT NULL DEFAULT 0,
+    recurrence_rule TEXT
+);
+
+CREATE INDEX idx_tasks_owner_id ON tasks (owner_id);
+CREATE INDEX idx_tasks_status ON tasks (owner_id, status) WHERE deleted_at IS NULL;
+CREATE INDEX idx_tasks_priority ON tasks (owner_id, priority) WHERE deleted_at IS NULL;
+CREATE INDEX idx_tasks_due_date ON tasks (owner_id, due_date) WHERE deleted_at IS NULL;
+CREATE INDEX idx_tasks_project_id ON tasks (project_id) WHERE deleted_at IS NULL;
+CREATE INDEX idx_tasks_parent_id ON tasks (parent_id) WHERE deleted_at IS NULL;
+
+-- Task Tags (many-to-many)
+CREATE TABLE task_tags (
+    task_id UUID NOT NULL REFERENCES tasks(id),
+    tag_id UUID NOT NULL REFERENCES tags(id),
+    PRIMARY KEY (task_id, tag_id)
+);
+
+CREATE INDEX idx_task_tags_task_id ON task_tags (task_id);
+CREATE INDEX idx_task_tags_tag_id ON task_tags (tag_id);
+
+-- Task Dependencies (Layer 3)
+-- task_id is blocked by blocks_task_id (blocker)
+CREATE TABLE task_dependencies (
+    task_id UUID NOT NULL REFERENCES tasks(id),
+    blocks_task_id UUID NOT NULL REFERENCES tasks(id),
+    PRIMARY KEY (task_id, blocks_task_id),
+    CHECK (task_id != blocks_task_id)
+);
+
+CREATE INDEX idx_task_dependencies_task_id ON task_dependencies (task_id);
+CREATE INDEX idx_task_dependencies_blocks ON task_dependencies (blocks_task_id);
+
+-- Task Reminders (Layer 2)
+CREATE TABLE task_reminders (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    task_id UUID NOT NULL REFERENCES tasks(id),
+    type TEXT NOT NULL CHECK (type IN ('push', 'email', 'webhook', 'telegram', 'nostr')),
+    config JSONB NOT NULL DEFAULT '{}',
+    scheduled_at TIMESTAMPTZ NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX idx_task_reminders_task_id ON task_reminders (task_id);
+CREATE INDEX idx_task_reminders_scheduled ON task_reminders (scheduled_at);
+
+-- Task Webhooks (Layer 3)
+CREATE TABLE task_webhooks (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    owner_id UUID NOT NULL REFERENCES users(id),
+    url TEXT NOT NULL,
+    events JSONB NOT NULL DEFAULT '[]',
+    secret TEXT,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX idx_task_webhooks_owner_id ON task_webhooks (owner_id);

sqlc/queries/projects.sql

@@ -0,0 +1,54 @@
+-- name: CreateProject :one
+INSERT INTO projects (id, owner_id, name, color, is_shared, deadline, sort_order)
+VALUES ($1, $2, $3, $4, COALESCE($5, false), $6, COALESCE($7, 0))
+RETURNING *;
+
+-- name: GetProjectByID :one
+SELECT * FROM projects
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL;
+
+-- name: ListProjects :many
+SELECT * FROM projects
+WHERE owner_id = @owner_id AND deleted_at IS NULL
+ORDER BY sort_order ASC, name ASC;
+
+-- name: ListProjectsForUser :many
+SELECT p.* FROM projects p
+LEFT JOIN project_members pm ON pm.project_id = p.id AND pm.user_id = @user_id
+WHERE (p.owner_id = @user_id OR pm.user_id = @user_id)
+  AND p.deleted_at IS NULL
+ORDER BY p.sort_order ASC, p.name ASC;
+
+-- name: UpdateProject :one
+UPDATE projects
+SET name = COALESCE(sqlc.narg('name'), name),
+    color = COALESCE(sqlc.narg('color'), color),
+    is_shared = COALESCE(sqlc.narg('is_shared'), is_shared),
+    deadline = sqlc.narg('deadline'),
+    sort_order = COALESCE(sqlc.narg('sort_order'), sort_order),
+    updated_at = now()
+WHERE id = @id AND owner_id = @owner_id AND deleted_at IS NULL
+RETURNING *;
+
+-- name: SoftDeleteProject :exec
+UPDATE projects SET deleted_at = now(), updated_at = now()
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL;
+
+-- name: AddProjectMember :exec
+INSERT INTO project_members (project_id, user_id, role)
+VALUES ($1, $2, $3)
+ON CONFLICT (project_id, user_id) DO UPDATE SET role = EXCLUDED.role;
+
+-- name: RemoveProjectMember :exec
+DELETE FROM project_members
+WHERE project_id = $1 AND user_id = $2;
+
+-- name: ListProjectMembers :many
+SELECT pm.project_id, pm.user_id, pm.role, u.email
+FROM project_members pm
+JOIN users u ON u.id = pm.user_id
+WHERE pm.project_id = $1;
+
+-- name: GetProjectMember :one
+SELECT * FROM project_members
+WHERE project_id = $1 AND user_id = $2;

sqlc/queries/tags.sql

@@ -0,0 +1,40 @@
+-- name: CreateTag :one
+INSERT INTO tags (id, owner_id, name, color)
+VALUES ($1, $2, $3, COALESCE($4, '#6B7280'))
+RETURNING *;
+
+-- name: GetTagByID :one
+SELECT * FROM tags
+WHERE id = $1 AND owner_id = $2;
+
+-- name: ListTagsByOwner :many
+SELECT * FROM tags
+WHERE owner_id = $1
+ORDER BY name ASC;
+
+-- name: UpdateTag :one
+UPDATE tags
+SET name = COALESCE(sqlc.narg('name'), name),
+    color = COALESCE(sqlc.narg('color'), color)
+WHERE id = @id AND owner_id = @owner_id
+RETURNING *;
+
+-- name: DeleteTag :exec
+DELETE FROM tags WHERE id = $1 AND owner_id = $2;
+
+-- name: AttachTagToTask :exec
+INSERT INTO task_tags (task_id, tag_id)
+VALUES ($1, $2)
+ON CONFLICT (task_id, tag_id) DO NOTHING;
+
+-- name: DetachTagFromTask :exec
+DELETE FROM task_tags
+WHERE task_id = $1 AND tag_id = $2;
+
+-- name: ListTagsByTask :many
+SELECT t.* FROM tags t
+JOIN task_tags tt ON tt.tag_id = t.id
+WHERE tt.task_id = $1;
+
+-- name: ListTaskIDsByTag :many
+SELECT task_id FROM task_tags WHERE tag_id = $1;

sqlc/queries/task_dependencies.sql

@@ -0,0 +1,25 @@
+-- name: AddTaskDependency :exec
+INSERT INTO task_dependencies (task_id, blocks_task_id)
+VALUES ($1, $2)
+ON CONFLICT (task_id, blocks_task_id) DO NOTHING;
+
+-- name: RemoveTaskDependency :exec
+DELETE FROM task_dependencies
+WHERE task_id = $1 AND blocks_task_id = $2;
+
+-- name: ListTaskBlockers :many
+SELECT t.* FROM tasks t
+JOIN task_dependencies td ON td.blocks_task_id = t.id
+WHERE td.task_id = $1 AND t.deleted_at IS NULL;
+
+-- name: ListTasksBlockedBy :many
+SELECT t.* FROM tasks t
+JOIN task_dependencies td ON td.task_id = t.id
+WHERE td.blocks_task_id = $1 AND t.deleted_at IS NULL;
+
+-- name: CheckDirectCircularDependency :one
+-- Direct cycle: blocks_task_id is blocked by task_id (would create A->B and B->A)
+SELECT EXISTS(
+  SELECT 1 FROM task_dependencies
+  WHERE task_id = $2 AND blocks_task_id = $1
+) AS has_circle;

sqlc/queries/task_reminders.sql

@@ -0,0 +1,26 @@
+-- name: CreateTaskReminder :one
+INSERT INTO task_reminders (id, task_id, type, config, scheduled_at)
+VALUES ($1, $2, $3, COALESCE($4, '{}'), $5)
+RETURNING *;
+
+-- name: GetTaskReminderByID :one
+SELECT * FROM task_reminders
+WHERE id = $1;
+
+-- name: ListTaskReminders :many
+SELECT * FROM task_reminders
+WHERE task_id = $1
+ORDER BY scheduled_at ASC;
+
+-- name: ListTaskRemindersDueBefore :many
+SELECT tr.*, t.owner_id, t.title
+FROM task_reminders tr
+JOIN tasks t ON t.id = tr.task_id
+WHERE tr.scheduled_at <= $1
+  AND t.deleted_at IS NULL;
+
+-- name: DeleteTaskReminder :exec
+DELETE FROM task_reminders WHERE id = $1;
+
+-- name: DeleteTaskRemindersByTask :exec
+DELETE FROM task_reminders WHERE task_id = $1;

sqlc/queries/task_webhooks.sql

@@ -0,0 +1,16 @@
+-- name: CreateTaskWebhook :one
+INSERT INTO task_webhooks (id, owner_id, url, events, secret)
+VALUES ($1, $2, $3, COALESCE($4, '[]'), $5)
+RETURNING *;
+
+-- name: GetTaskWebhookByID :one
+SELECT * FROM task_webhooks
+WHERE id = $1 AND owner_id = $2;
+
+-- name: ListTaskWebhooksByOwner :many
+SELECT * FROM task_webhooks
+WHERE owner_id = $1
+ORDER BY created_at DESC;
+
+-- name: DeleteTaskWebhook :exec
+DELETE FROM task_webhooks WHERE id = $1 AND owner_id = $2;

sqlc/queries/tasks.sql

@@ -0,0 +1,125 @@
+-- name: CreateTask :one
+INSERT INTO tasks (id, owner_id, title, description, status, priority, due_date, project_id, parent_id, sort_order, recurrence_rule)
+VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)
+RETURNING *;
+
+-- name: GetTaskByID :one
+SELECT * FROM tasks
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL;
+
+-- name: GetTaskByIDForUpdate :one
+SELECT * FROM tasks
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL
+FOR UPDATE;
+
+-- name: ListTasks :many
+SELECT t.* FROM tasks t
+WHERE t.owner_id = @owner_id
+  AND t.deleted_at IS NULL
+  AND t.parent_id IS NULL
+  AND (sqlc.narg('status')::TEXT IS NULL OR t.status = sqlc.narg('status')::TEXT)
+  AND (sqlc.narg('priority')::TEXT IS NULL OR t.priority = sqlc.narg('priority')::TEXT)
+  AND (sqlc.narg('project_id')::UUID IS NULL OR t.project_id = sqlc.narg('project_id')::UUID)
+  AND (sqlc.narg('due_from')::TIMESTAMPTZ IS NULL OR t.due_date >= sqlc.narg('due_from')::TIMESTAMPTZ)
+  AND (sqlc.narg('due_to')::TIMESTAMPTZ IS NULL OR t.due_date <= sqlc.narg('due_to')::TIMESTAMPTZ)
+  AND (
+    sqlc.narg('cursor_time')::TIMESTAMPTZ IS NULL
+    OR (t.created_at, t.id) < (sqlc.narg('cursor_time')::TIMESTAMPTZ, sqlc.narg('cursor_id')::UUID)
+  )
+ORDER BY t.created_at DESC, t.id DESC
+LIMIT @lim;
+
+-- name: ListTasksByDueDate :many
+SELECT t.* FROM tasks t
+WHERE t.owner_id = @owner_id
+  AND t.deleted_at IS NULL
+  AND t.parent_id IS NULL
+  AND (sqlc.narg('status')::TEXT IS NULL OR t.status = sqlc.narg('status')::TEXT)
+  AND (sqlc.narg('priority')::TEXT IS NULL OR t.priority = sqlc.narg('priority')::TEXT)
+  AND (sqlc.narg('project_id')::UUID IS NULL OR t.project_id = sqlc.narg('project_id')::UUID)
+  AND (sqlc.narg('due_from')::TIMESTAMPTZ IS NULL OR t.due_date >= sqlc.narg('due_from')::TIMESTAMPTZ)
+  AND (sqlc.narg('due_to')::TIMESTAMPTZ IS NULL OR t.due_date <= sqlc.narg('due_to')::TIMESTAMPTZ)
+ORDER BY COALESCE(t.due_date, '9999-12-31'::timestamptz) ASC NULLS LAST, t.id ASC
+LIMIT @lim;
+
+-- name: ListTasksByPriority :many
+SELECT t.* FROM tasks t
+WHERE t.owner_id = @owner_id
+  AND t.deleted_at IS NULL
+  AND t.parent_id IS NULL
+  AND (sqlc.narg('status')::TEXT IS NULL OR t.status = sqlc.narg('status')::TEXT)
+  AND (sqlc.narg('priority')::TEXT IS NULL OR t.priority = sqlc.narg('priority')::TEXT)
+  AND (sqlc.narg('project_id')::UUID IS NULL OR t.project_id = sqlc.narg('project_id')::UUID)
+  AND (sqlc.narg('due_from')::TIMESTAMPTZ IS NULL OR t.due_date >= sqlc.narg('due_from')::TIMESTAMPTZ)
+  AND (sqlc.narg('due_to')::TIMESTAMPTZ IS NULL OR t.due_date <= sqlc.narg('due_to')::TIMESTAMPTZ)
+ORDER BY CASE t.priority
+  WHEN 'critical' THEN 1
+  WHEN 'high' THEN 2
+  WHEN 'medium' THEN 3
+  WHEN 'low' THEN 4
+  ELSE 5
+END ASC, t.created_at DESC, t.id DESC
+LIMIT @lim;
+
+-- name: ListTasksWithTag :many
+SELECT DISTINCT t.* FROM tasks t
+JOIN task_tags tt ON tt.task_id = t.id
+WHERE t.owner_id = @owner_id
+  AND t.deleted_at IS NULL
+  AND t.parent_id IS NULL
+  AND tt.tag_id = ANY(@tag_ids)
+  AND (sqlc.narg('status')::TEXT IS NULL OR t.status = sqlc.narg('status')::TEXT)
+  AND (sqlc.narg('project_id')::UUID IS NULL OR t.project_id = sqlc.narg('project_id')::UUID)
+ORDER BY t.created_at DESC, t.id DESC
+LIMIT @lim;
+
+-- name: UpdateTask :one
+UPDATE tasks
+SET title = COALESCE(sqlc.narg('title'), title),
+    description = COALESCE(sqlc.narg('description'), description),
+    status = COALESCE(sqlc.narg('status'), status),
+    priority = COALESCE(sqlc.narg('priority'), priority),
+    due_date = sqlc.narg('due_date'),
+    project_id = sqlc.narg('project_id'),
+    sort_order = COALESCE(sqlc.narg('sort_order'), sort_order),
+    recurrence_rule = sqlc.narg('recurrence_rule'),
+    updated_at = now()
+WHERE id = @id AND owner_id = @owner_id AND deleted_at IS NULL
+RETURNING *;
+
+-- name: SoftDeleteTask :exec
+UPDATE tasks SET deleted_at = now(), updated_at = now()
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL;
+
+-- name: HardDeleteTask :exec
+DELETE FROM tasks WHERE id = $1 AND owner_id = $2;
+
+-- name: MarkTaskComplete :one
+UPDATE tasks
+SET status = 'done', completed_at = now(), updated_at = now()
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL
+RETURNING *;
+
+-- name: MarkTaskUncomplete :one
+UPDATE tasks
+SET status = COALESCE(sqlc.narg('new_status'), 'todo'), completed_at = NULL, updated_at = now()
+WHERE id = $1 AND owner_id = $2 AND deleted_at IS NULL
+RETURNING *;
+
+-- name: ListSubtasks :many
+SELECT * FROM tasks
+WHERE parent_id = $1 AND owner_id = $2 AND deleted_at IS NULL
+ORDER BY sort_order ASC, created_at ASC;
+
+-- name: CountSubtasksByStatus :one
+SELECT
+  COUNT(*) FILTER (WHERE status = 'done') AS done_count,
+  COUNT(*) AS total_count
+FROM tasks
+WHERE parent_id = $1 AND deleted_at IS NULL;
+
+-- name: ListTasksWithRecurrence :many
+SELECT * FROM tasks
+WHERE owner_id = $1 AND deleted_at IS NULL
+  AND recurrence_rule IS NOT NULL
+  AND parent_id IS NULL;

sqlc/schema.sql

@@ -197,3 +197,112 @@ CREATE TABLE calendar_subscriptions (
 );
 
 CREATE INDEX idx_calendar_subscriptions_calendar_id ON calendar_subscriptions (calendar_id);
+
+-- Projects (Layer 2)
+CREATE TABLE projects (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    owner_id UUID NOT NULL REFERENCES users(id),
+    name TEXT NOT NULL,
+    color TEXT NOT NULL DEFAULT '#3B82F6',
+    is_shared BOOLEAN NOT NULL DEFAULT false,
+    deadline TIMESTAMPTZ,
+    sort_order INTEGER NOT NULL DEFAULT 0,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    deleted_at TIMESTAMPTZ
+);
+
+CREATE INDEX idx_projects_owner_id ON projects (owner_id);
+
+-- Project Members (Layer 2 shared projects)
+CREATE TABLE project_members (
+    project_id UUID NOT NULL REFERENCES projects(id),
+    user_id UUID NOT NULL REFERENCES users(id),
+    role TEXT NOT NULL CHECK (role IN ('owner', 'editor', 'viewer')),
+    PRIMARY KEY (project_id, user_id)
+);
+
+CREATE INDEX idx_project_members_project_id ON project_members (project_id);
+
+-- Tags (Layer 2)
+CREATE TABLE tags (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    owner_id UUID NOT NULL REFERENCES users(id),
+    name TEXT NOT NULL,
+    color TEXT NOT NULL DEFAULT '#6B7280',
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX idx_tags_owner_id ON tags (owner_id);
+
+-- Tasks (Layer 1 core)
+CREATE TABLE tasks (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    owner_id UUID NOT NULL REFERENCES users(id),
+    title TEXT NOT NULL,
+    description TEXT,
+    status TEXT NOT NULL DEFAULT 'todo' CHECK (status IN ('todo', 'in_progress', 'done', 'archived')),
+    priority TEXT NOT NULL DEFAULT 'medium' CHECK (priority IN ('low', 'medium', 'high', 'critical')),
+    due_date TIMESTAMPTZ,
+    completed_at TIMESTAMPTZ,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    deleted_at TIMESTAMPTZ,
+    project_id UUID REFERENCES projects(id),
+    parent_id UUID REFERENCES tasks(id),
+    sort_order INTEGER NOT NULL DEFAULT 0,
+    recurrence_rule TEXT
+);
+
+CREATE INDEX idx_tasks_owner_id ON tasks (owner_id);
+CREATE INDEX idx_tasks_status ON tasks (owner_id, status) WHERE deleted_at IS NULL;
+CREATE INDEX idx_tasks_priority ON tasks (owner_id, priority) WHERE deleted_at IS NULL;
+CREATE INDEX idx_tasks_due_date ON tasks (owner_id, due_date) WHERE deleted_at IS NULL;
+CREATE INDEX idx_tasks_project_id ON tasks (project_id) WHERE deleted_at IS NULL;
+CREATE INDEX idx_tasks_parent_id ON tasks (parent_id) WHERE deleted_at IS NULL;
+
+-- Task Tags (many-to-many)
+CREATE TABLE task_tags (
+    task_id UUID NOT NULL REFERENCES tasks(id),
+    tag_id UUID NOT NULL REFERENCES tags(id),
+    PRIMARY KEY (task_id, tag_id)
+);
+
+CREATE INDEX idx_task_tags_task_id ON task_tags (task_id);
+CREATE INDEX idx_task_tags_tag_id ON task_tags (tag_id);
+
+-- Task Dependencies (Layer 3)
+CREATE TABLE task_dependencies (
+    task_id UUID NOT NULL REFERENCES tasks(id),
+    blocks_task_id UUID NOT NULL REFERENCES tasks(id),
+    PRIMARY KEY (task_id, blocks_task_id),
+    CHECK (task_id != blocks_task_id)
+);
+
+CREATE INDEX idx_task_dependencies_task_id ON task_dependencies (task_id);
+CREATE INDEX idx_task_dependencies_blocks ON task_dependencies (blocks_task_id);
+
+-- Task Reminders (Layer 2)
+CREATE TABLE task_reminders (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    task_id UUID NOT NULL REFERENCES tasks(id),
+    type TEXT NOT NULL CHECK (type IN ('push', 'email', 'webhook', 'telegram', 'nostr')),
+    config JSONB NOT NULL DEFAULT '{}',
+    scheduled_at TIMESTAMPTZ NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX idx_task_reminders_task_id ON task_reminders (task_id);
+CREATE INDEX idx_task_reminders_scheduled ON task_reminders (scheduled_at);
+
+-- Task Webhooks (Layer 3)
+CREATE TABLE task_webhooks (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    owner_id UUID NOT NULL REFERENCES users(id),
+    url TEXT NOT NULL,
+    events JSONB NOT NULL DEFAULT '[]',
+    secret TEXT,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX idx_task_webhooks_owner_id ON task_webhooks (owner_id);