New Features
- Hardware Volume Button Control - Physical volume buttons now control the selected Music Assistant player's volume instead of device volume
- Works for all MA players (speakers, groups, etc.)
- Builtin player (phone) uses native device volume as before
- Automatically switches behavior based on selected player
Technical
- Native Android volume button interception via MethodChannel
- Dynamic interception toggling based on player selection
- FlutterVolumeController integration for builtin player