Extraction is now fully async via Celery — UI shows a live progress panel,
job continues even if page is closed. Large documents are processed in
50-page chunks to extract all questions (not just first ~50 pages).
Backend:
- app/tasks/quiz_tasks.py: new Celery task 'extract_quiz'
- Writes step-by-step progress to Redis (extraction:steps:{job_id})
- Splits large page ranges into 50-page chunks, processes each separately
- Reports per-chunk results and running total
- Falls back to synchronous if Celery/Redis unavailable
- POST /quizzes/ now returns {job_id, status:"pending"} immediately
- GET /quizzes/job/{job_id} polls progress: steps[], status, quiz_id on completion
- Celery task list updated to include quiz_tasks
Frontend (DocumentDetailPage):
- ExtractionProgress modal component: monospace step log, auto-scrolls, spinner
- Polls job status every 2 seconds via /quizzes/job/{job_id}
- "Open Quiz →" button appears when done
- "✕ closes — job continues in background" shown while running
- beforeunload warning when job is active (preventing accidental close)
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
