Updated config flow's initial setup.
Ecowitt stations does not require `API_ID` and `API_KEY`, so we need to
separate Ecowitt setup from PWS/WSLink setup.
- Add detailed architecture overview in __init__.py
- Introduce shared runtime keys in data.py to avoid key conflicts
- Implement dual route dispatcher for webhook endpoint selection
- Enhance sensor platform for dynamic sensor addition without reloads
- Rename battery level "unknown" to "drained" with updated icons
- Improve utils.py with centralized helpers for remapping and discovery
- Update translations and strings for consistency