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/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;