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/sqlc.yaml

@@ -0,0 +1,14 @@
+version: "2"
+sql:
+  - schema: "../../../migrations/"
+    queries: "queries/"
+    engine: "postgresql"
+    gen:
+      go:
+        package: "generated"
+        out: "generated"
+        emit_json_tags: true
+        emit_prepared_queries: false
+        emit_interface: true
+        emit_exact_table_names: false
+        sql_package: "pgx/v5"