- Add volume control screen with sliders for media, ringtone, and alarm
- Update device settings via PUT /devices with CSV (same as language)
- Extract DeviceCsvBuilder to legacy_shared (shared between language and volume)
- Create Riverpod provider for DeviceUpdateDatasource
- Extract VolumeThumbShape to separate widget file
- Merge sound mode feature (SET_SOUND_MODE command, pending backend whitelist)
- Fix sound screen overflow with SingleChildScrollView