Decouple weather data fetching from reverse geocoding so that
weather loads as soon as coordinates are available, even when
Nominatim is unreachable (e.g. mainland China).
- Fetch Open-Meteo weather immediately once lat/lon are known.
- Resolve city name in parallel via Nominatim -> Photon -> BigDataCloud.
- If all reverse geocoding fails, keep displaying weather with a
placeholder city name.
- Skip reverse geocoding entirely when the user has configured a
city name.
- Fall back to ip-api.com when GeoClue2 is unavailable or returns
zero coordinates.
- Add request-generation tracking to discard stale geocoding
responses after location changes.
- Hold explicit WeatherService refs in bar widget and dashboard tab.
Co-authored-by: lingdiansr <[email protected]>
