fix: allow lint to pass

[OkeyAmy]

Summary

• Add an Open-Meteo solar forecast client with IndexedDB caching, stale-cache fallback, and historical-average degradation when live data is unavailable.
• Add a solar forecast hook that maps configured facility coordinates to 48 hourly irradiance points and battery capacity estimates.
• Add a solar battery gauge with manual refresh, last-updated copy, cached/fallback indicators, and a 48-hour sparkline.
• Surface solar/battery node power source metadata in the facility dashboard and render forecast cards only for non-grid nodes.

Closes #50

[JamesEjembi]

LGTM