Centralize brightness handling
- Fix: Brightness no longer resets to 50% after update — defaults to 100% until config restores saved value
- Refactor: All brightness conversion centralized in
LCDDevice— CLI, API, and GUI adapters no longer bypass the service layer - New:
LCDDevice.from_service(),restore_device_settings(),load_last_theme()methods for clean adapter wiring - Removed: Scattered
{1: 25, 2: 50, 3: 100}maps from 6 files → singleBRIGHTNESS_LEVELSconstant incore/models.py - Tests: 4665 (+5 new for LCDDevice brightness/theme methods)