- Split summarizer into summary_generator and summary_persister modules
- Refactor pdf_image_extractor to two-phase pipeline with PicoDet layout detection
- Add layout_detector service for PicoDet-S_layout_3cls integration
- Add exceptions module with ConflictError and NotFoundError
- Improve admin dashboard with better statistics and task management
- Add design review document with system optimization suggestions
- Add new tests for crawler, pdf_downloader, pipeline, and summary_utils
- Update dependencies and configuration
- Clean up dead code and improve error handling
- Add POST /admin/crawl with TaskLock-based reentrancy guard
- Add POST /admin/cleanup (tmp files older than 24h) with CrawlLog
- Add POST /admin/delete with date range and 'DELETE' confirm token
- Add GET /admin/logs (paginated CrawlLog + DataDeleteJob viewer)
- Add app/services/cleaner.py (cleanup_tmp, delete_papers_by_date_range)
- Add app/services/scheduler.py (APScheduler daily crawl/cleanup jobs)
- Wire scheduler startup/shutdown hooks in app/main.py
- Add admin nav link in base.html and APP_HOST security warning
- Add apscheduler>=3.10 dependency
- Add tests/test_admin_phase4.py covering the new endpoints