New features:
- Auto Play/Pause (pause when headphones are removed)
- Auto-answer calls toggle
- Power Off from the app
- Enter Bluetooth Pairing Mode
- Device names in multipoint list now resolved from headphone memory (no more raw MAC addresses)
- Now Playing source device shown in status card
- Persistent notification: ANC toggle, mode cycling (favourites only), Power Off
- ANC slider inverted: higher = more noise cancellation
- Mode 255 shown as "Custom" instead of raw index
- Immediate UI refresh after every action (no more waiting for the 15 s poll)

