Fix COOL/AUTO modes, make climate actions async, and add translations
- Fixed IntEnum truthiness bug where COOL mode (0) and AUTO fan speed (0) were ignored.
- Converted climate control actions (HVAC mode, temperature, fan mode) to asynchronous methods with executor threads to prevent blocking Home Assistant's event loop.
- Added turn_on / turn_off helper methods to properly support the climate platform features.
- Added strings.json and translations (de, en) for clean configuration flow in the UI.