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

backend/requirements.txt

@@ -0,0 +1,9 @@
+PyJWT>=2.8.0
+openai>=1.12.0
+boto3>=1.34.0
+requests>=2.31.0
+qrcode>=7.4.2
+reportlab>=4.0.0
+Pillow>=10.0.0
+pgvector>=0.2.0
+psycopg2-binary>=2.9.0