Temperature display always showed 'unavailable' because formatDayTemperature()
read dayTemperatures from closure, which Svelte 4's compiler doesn't track in
template expressions. Same issue affected getLocationConnector() reading
connectorMetricsMap from closure.
Fix: pass both state variables as explicit function parameters so they appear
in template expressions and trigger re-renders on async updates.
Also improve optimize button diagnostics with console logging and better
toast feedback when items lack coordinates.