fix: stale closure in updateRouteForDay causes route to disappear on place click

useCallback captured tripStore at creation time (dep: [routeCalcEnabled]).
If assignments were empty on first render (trip still loading), the callback
would permanently see empty assignments and call setRoute(null) whenever
invoked — e.g. when clicking a place triggers onSelectDay → updateRouteForDay.

Fix: store tripStore in a ref updated on every render so the callback always
reads the latest assignments without needing to be recreated.

client/src/hooks/useRouteCalculation.ts

@@ -15,11 +15,14 @@ export function useRouteCalculation(tripStore: TripStoreState, selectedDayId: nu
   const [routeSegments, setRouteSegments] = useState<RouteSegment[]>([])
   const routeCalcEnabled = useSettingsStore((s) => s.settings.route_calculation) !== false
   const routeAbortRef = useRef<AbortController | null>(null)
+  // Keep a ref to the latest tripStore so updateRouteForDay never has a stale closure
+  const tripStoreRef = useRef(tripStore)
+  tripStoreRef.current = tripStore
 
   const updateRouteForDay = useCallback(async (dayId: number | null) => {
     if (routeAbortRef.current) routeAbortRef.current.abort()
     if (!dayId) { setRoute(null); setRouteSegments([]); return }
-    const currentAssignments = tripStore.assignments || {}
+    const currentAssignments = tripStoreRef.current.assignments || {}
     const da = (currentAssignments[String(dayId)] || []).slice().sort((a, b) => a.order_index - b.order_index)
     const waypoints = da.map((a) => a.place).filter((p) => p?.lat && p?.lng)
     if (waypoints.length < 2) { setRoute(null); setRouteSegments([]); return }