feat: QA fixes, new APIs (assignments, rubrics, custom exams), Generation page enhancements

- Fix ELAI video generation (correct render endpoint, script splitting for 60s limit)
- Fix speaking script generation error handling and empty response display
- Add custom exam list API (GET /api/exam/custom/list)
- Add assignments REST API (list, create, get)
- Add rubrics REST API (list, create)
- Enhance Generation page: dynamic exam structures, auto-module selection, preview dialog, audio player
- Improve submit feedback with exam ID and status in toast notifications
- Fix ExamsListPage to show both custom exams and exam sessions
- Connect RubricsPage to backend API with fallback data
- Add Dockerfile, docker-compose.yml, requirements.txt for deployment
- Fix placement, grading, scoring, and auth controllers
- Add ErrorBoundary component for frontend resilience
- Add QA report and credentials documentation

Made-with: Cursor

custom_addons/encoach_ai/controllers/ai_controller.py

@@ -347,7 +347,8 @@ class AIController(http.Controller):
             ]
             return _json_response(ai.chat_json(messages, action=f"exam_generate_{module}"))
         except Exception as e:
-            return _json_response({"questions": [], "error": str(e)})
+            _logger.exception("exam_generate %s failed: %s", module, e)
+            return _json_response({"questions": [], "error": str(e)}, 500)
 
     def _generate_passage(self, ai, body):
         topic = body.get("topic", "general knowledge")