feat: search, multi-stop routing, and route display

Full navigation UI with:
- Search bar with 150ms debounced autocomplete from /api/geocode
- Keyboard navigation (arrow keys, Enter, Escape)
- Exact match badge for verified address results
- Multi-stop list with drag-to-reorder (dnd-kit)
- 10-stop cap with disabled state
- Mode selector (drive/walk/bike)
- Valhalla route display with per-leg color polyline
- Maneuver list with instructions, distance, time remaining
- Click maneuver to fly map to that point
- Optimize stops button (3+ stops, uses /optimized_route)
- Responsive: side panel (desktop ≥768px), bottom sheet (mobile)
- Stop pins: green origin, red destination, blue intermediate
- Pin popup with remove button
- Geolocation permission requested on first route, not on load
- Error handling for unroutable pairs
- nginx proxy for /api/ and /valhalla/ endpoints

Dependencies added: zustand, @dnd-kit/core, @dnd-kit/sortable,
@dnd-kit/utilities

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/StopList.jsx

@@ -0,0 +1,58 @@
+import {
+  DndContext,
+  closestCenter,
+  KeyboardSensor,
+  PointerSensor,
+  useSensor,
+  useSensors,
+} from '@dnd-kit/core'
+import {
+  arrayMove,
+  SortableContext,
+  sortableKeyboardCoordinates,
+  verticalListSortingStrategy,
+} from '@dnd-kit/sortable'
+import { useStore } from '../store'
+import StopItem from './StopItem'
+
+export default function StopList() {
+  const stops = useStore((s) => s.stops)
+  const reorderStops = useStore((s) => s.reorderStops)
+  const geoPermission = useStore((s) => s.geoPermission)
+
+  const sensors = useSensors(
+    useSensor(PointerSensor, { activationConstraint: { distance: 5 } }),
+    useSensor(KeyboardSensor, { coordinateGetter: sortableKeyboardCoordinates })
+  )
+
+  function handleDragEnd(event) {
+    const { active, over } = event
+    if (!over || active.id === over.id) return
+
+    const oldIndex = stops.findIndex((s) => s.id === active.id)
+    const newIndex = stops.findIndex((s) => s.id === over.id)
+    reorderStops(arrayMove(stops, oldIndex, newIndex))
+  }
+
+  if (stops.length === 0) {
+    return (
+      <div className="text-gray-500 text-xs px-2 py-3 text-center">
+        {geoPermission === 'denied'
+          ? 'Add a starting point and destination above'
+          : 'Search and add stops to build your route'}
+      </div>
+    )
+  }
+
+  return (
+    <DndContext sensors={sensors} collisionDetection={closestCenter} onDragEnd={handleDragEnd}>
+      <SortableContext items={stops.map((s) => s.id)} strategy={verticalListSortingStrategy}>
+        <div className="flex flex-col gap-1">
+          {stops.map((stop, i) => (
+            <StopItem key={stop.id} stop={stop} index={i} total={stops.length} />
+          ))}
+        </div>
+      </SortableContext>
+    </DndContext>
+  )
+}