aaf6e551a0
Reuses the saved weather location's lat/lon to fetch us_aqi from Open-Meteo's air-quality API (no key), folded into the existing 2h forecast cache (bumped v1->v2). AQI is best-effort: a failed fetch never sinks the forecast. Shows as a header chip and a colored row on the forecast card; both self-hide when there is no reading.