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

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;