fix(map): call updateBoundary directly, remove useEffect

The useEffect-based boundary rendering was unreliable due to React's
state lifecycle - the effect would fire before boundary data arrived
from the API, then not re-trigger properly when data was populated.

New approach:
- Remove the boundary useEffect entirely
- Define updateBoundary function in map load handler
- Store function reference in Zustand store and local ref
- PlaceCard calls updateBoundary(geometry) directly when API returns
- Click handlers call updateBoundary(null) to clear

This bypasses React's render cycle - the map library handles its own
state and we tell it what to draw when we have the data.

Test sequence:
- Click Twin Falls → boundary shows on first click
- Click Kimberly → boundary shows on first click
- Switch between them → old clears, new shows
- Click empty map → boundary clears

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/store.js

@@ -65,6 +65,10 @@ export const useStore = create((set, get) => ({
   pendingDestination: null, // place waiting for a starting point (GPS-denied Directions flow)
 
   setSelectedPlace: (place) => set({ selectedPlace: place }),
+
+  // Boundary rendering function - set by MapView, called by PlaceCard
+  updateBoundary: null,
+  setUpdateBoundary: (fn) => set({ updateBoundary: fn }),
   clearSelectedPlace: () => set({ selectedPlace: null, clickMarker: null }),
   setClickMarker: (marker) => set({ clickMarker: marker }),
   clearClickMarker: () => set({ clickMarker: null }),