fix: Auto-seed official subjects table to satisfy foreign key constraints on courses creation

backend/app/Controllers/TeacherController.php

@@ -7,6 +7,7 @@ use App\Core\Response;
 use App\Core\Database;
 use App\Core\Security;
 use App\Core\Validator;
+use App\Services\CurriculumService;
 
 class TeacherController
 {
@@ -167,6 +168,7 @@ class TeacherController
      */
     public function getCourses(Request $request, Response $response): void
     {
+        CurriculumService::ensureSchema();
         $userId = (int)$request->user_id;
 
         $courses = Database::select(