feat: add tenant and user management with migrations, handlers, and tests

- Implemented tenant and user management features including:
  - Tenant creation and management with associated migrations.
  - User creation and management with associated migrations.
  - Tenant membership management with associated migrations.
  - Platform user roles management with associated migrations.
  - Quota management with associated migrations.
  - Article and template management with associated migrations.
- Added HTTP handlers for templates and workspaces.
- Created tests for protected and public routes.
- Introduced a script to check tenant scope in SQL queries.
- Documented task plan for backend completion and frontend foundation.

server/internal/tenant/repository/queries/quota.sql

@@ -0,0 +1,30 @@
+-- name: GetCurrentBalance :one
+SELECT COALESCE(
+    (SELECT balance_after FROM tenant_quota_ledgers
+     WHERE tenant_id = sqlc.arg(tenant_id) AND quota_type = sqlc.arg(quota_type)
+     ORDER BY created_at DESC LIMIT 1), 0
+)::INT AS balance;
+
+-- name: InsertQuotaLedger :one
+INSERT INTO tenant_quota_ledgers (tenant_id, quota_type, delta, balance_after, reason, reference_type, reference_id)
+VALUES (sqlc.arg(tenant_id), sqlc.arg(quota_type), sqlc.arg(delta), sqlc.arg(balance_after),
+        sqlc.arg(reason), sqlc.arg(reference_type), sqlc.arg(reference_id))
+RETURNING id;
+
+-- name: CreateQuotaReservation :one
+INSERT INTO quota_reservations (tenant_id, quota_type, resource_type, resource_id, reserved_amount, status, expire_at)
+VALUES (sqlc.arg(tenant_id), sqlc.arg(quota_type), sqlc.arg(resource_type), sqlc.arg(resource_id),
+        sqlc.arg(reserved_amount), 'pending', sqlc.arg(expire_at))
+RETURNING id;
+
+-- name: UpdateQuotaReservationResource :exec
+UPDATE quota_reservations SET resource_id = sqlc.arg(resource_id), updated_at = NOW()
+WHERE id = sqlc.arg(id) AND tenant_id = sqlc.arg(tenant_id);
+
+-- name: ConfirmReservation :exec
+UPDATE quota_reservations SET status = 'confirmed', consumed_amount = reserved_amount, updated_at = NOW()
+WHERE id = sqlc.arg(id) AND tenant_id = sqlc.arg(tenant_id);
+
+-- name: RefundReservation :exec
+UPDATE quota_reservations SET status = 'refunded', refunded_amount = reserved_amount, updated_at = NOW()
+WHERE id = sqlc.arg(id) AND tenant_id = sqlc.arg(tenant_id);