- Add author_avatar_url to API schema and frontend interface
- Capture current playhead timestamp when creating comments
- Display user avatars in waveform markers instead of placeholders
- Improve marker visibility with better styling (size, borders, shadows)
- Fix TypeScript type errors for nullable timestamps
- Add debug logging for troubleshooting
This implements the full comment waveform integration as requested:
- Comments are created with exact playhead timestamps
- Waveform markers show at correct positions with user avatars
- Clicking markers scrolls to corresponding comments
- Backward compatible with existing comments without timestamps