- Add video_notes table and agent_queue table for persistent notes and AI agent tasks
- Add API endpoints: POST/GET /api/notes/{id}, POST /api/notes/migrate, agent queue endpoints
- Rebuild frontend: fix duplicate loadVideos(), non-blocking localStorage migration, notes UI
- Switch pip install to Tsinghua mirror for faster downloads in China
- Add backend/sync_rotation.json to .gitignore (runtime state)
Gan, Jimmy