- Rename 'Format' button to 'Quality' in settings (audio_quality/video_quality)
- Add DefaultAudioContainer and DefaultVideoContainer to UserPreferences
- Container settings now has Audio/Video sub-pickers (mp3/m4a/opus vs mp4/mkv/webm)
- Add migration 003 for new container columns
- Update repo layer and playlist flow for new fields
- Update back routing: back_quality, back_container
- Replace Type/Quality settings with single Format button -> Audio/Video sub-pickers
- Each sub-picker shows format options (bitrates for audio, resolutions for video)
- Replace DefaultQuality with DefaultAudioFormat/DefaultVideoFormat in UserPreferences
- Add DB migration 002 for new preference columns
- Update repo layer SQL queries for new schema
- Update playlist flow to use new preference fields
- Fix missing deleteaccount and delaccount_ callback routing
- Add back_format routing for format picker navigation