지도 마커 클러스터링 적용 (supercluster)

- 줌 16 이하에서 근접 마커를 숫자 원형 클러스터로 묶음
- 클러스터 클릭 시 해당 영역으로 자동 줌인
- 개별 마커 스타일/채널 색상 유지

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

frontend/src/components/MapView.tsx

@@ -8,6 +8,7 @@ import {
   InfoWindow,
   useMap,
 } from "@vis.gl/react-google-maps";
+import Supercluster from "supercluster";
 import type { Restaurant } from "@/lib/api";
 import { getCuisineIcon } from "@/lib/cuisine-icons";
 import Icon from "@/components/Icon";
@@ -62,10 +63,83 @@ interface MapViewProps {
   activeChannel?: string;
 }
 
+type RestaurantProps = { restaurant: Restaurant };
+type RestaurantFeature = Supercluster.PointFeature<RestaurantProps>;
+
+function useSupercluster(restaurants: Restaurant[]) {
+  const indexRef = useRef<Supercluster<{ restaurant: Restaurant }> | null>(null);
+
+  const points: RestaurantFeature[] = useMemo(
+    () =>
+      restaurants.map((r) => ({
+        type: "Feature" as const,
+        geometry: { type: "Point" as const, coordinates: [r.longitude, r.latitude] },
+        properties: { restaurant: r },
+      })),
+    [restaurants]
+  );
+
+  const index = useMemo(() => {
+    const sc = new Supercluster<{ restaurant: Restaurant }>({
+      radius: 60,
+      maxZoom: 16,
+      minPoints: 2,
+    });
+    sc.load(points);
+    indexRef.current = sc;
+    return sc;
+  }, [points]);
+
+  const getClusters = useCallback(
+    (bounds: MapBounds, zoom: number) => {
+      return index.getClusters(
+        [bounds.west, bounds.south, bounds.east, bounds.north],
+        Math.floor(zoom)
+      );
+    },
+    [index]
+  );
+
+  const getExpansionZoom = useCallback(
+    (clusterId: number): number => {
+      try {
+        return index.getClusterExpansionZoom(clusterId);
+      } catch {
+        return 17;
+      }
+    },
+    [index]
+  );
+
+  return { getClusters, getExpansionZoom, index };
+}
+
+function getClusterSize(count: number): number {
+  if (count < 10) return 36;
+  if (count < 50) return 42;
+  if (count < 100) return 48;
+  return 54;
+}
+
 function MapContent({ restaurants, selected, onSelectRestaurant, flyTo, activeChannel }: Omit<MapViewProps, "onMyLocation" | "onBoundsChanged">) {
   const map = useMap();
   const [infoTarget, setInfoTarget] = useState<Restaurant | null>(null);
+  const [zoom, setZoom] = useState(13);
+  const [bounds, setBounds] = useState<MapBounds | null>(null);
   const channelColors = useMemo(() => getChannelColorMap(restaurants), [restaurants]);
+  const { getClusters, getExpansionZoom } = useSupercluster(restaurants);
+
+  // Build a lookup for restaurants by id
+  const restaurantMap = useMemo(() => {
+    const m: Record<string, Restaurant> = {};
+    restaurants.forEach((r) => { m[r.id] = r; });
+    return m;
+  }, [restaurants]);
+
+  const clusters = useMemo(() => {
+    if (!bounds) return [];
+    return getClusters(bounds, zoom);
+  }, [bounds, zoom, getClusters]);
 
   const handleMarkerClick = useCallback(
     (r: Restaurant) => {
@@ -75,6 +149,41 @@ function MapContent({ restaurants, selected, onSelectRestaurant, flyTo, activeCh
     [onSelectRestaurant]
   );
 
+  const handleClusterClick = useCallback(
+    (clusterId: number, lng: number, lat: number) => {
+      if (!map) return;
+      const expansionZoom = Math.min(getExpansionZoom(clusterId), 18);
+      map.panTo({ lat, lng });
+      map.setZoom(expansionZoom);
+    },
+    [map, getExpansionZoom]
+  );
+
+  // Track camera changes for clustering
+  useEffect(() => {
+    if (!map) return;
+    const listener = map.addListener("idle", () => {
+      const b = map.getBounds();
+      const z = map.getZoom();
+      if (b && z != null) {
+        const ne = b.getNorthEast();
+        const sw = b.getSouthWest();
+        setBounds({ north: ne.lat(), south: sw.lat(), east: ne.lng(), west: sw.lng() });
+        setZoom(z);
+      }
+    });
+    // Trigger initial bounds
+    const b = map.getBounds();
+    const z = map.getZoom();
+    if (b && z != null) {
+      const ne = b.getNorthEast();
+      const sw = b.getSouthWest();
+      setBounds({ north: ne.lat(), south: sw.lat(), east: ne.lng(), west: sw.lng() });
+      setZoom(z);
+    }
+    return () => google.maps.event.removeListener(listener);
+  }, [map]);
+
   // Fly to a specific location (region filter)
   useEffect(() => {
     if (!map || !flyTo) return;
@@ -92,7 +201,46 @@ function MapContent({ restaurants, selected, onSelectRestaurant, flyTo, activeCh
 
   return (
     <>
-      {restaurants.map((r) => {
+      {clusters.map((feature) => {
+        const [lng, lat] = feature.geometry.coordinates;
+        const isCluster = feature.properties && "cluster" in feature.properties && feature.properties.cluster;
+
+        if (isCluster) {
+          const { cluster_id, point_count } = feature.properties as Supercluster.ClusterProperties;
+          const size = getClusterSize(point_count);
+          return (
+            <AdvancedMarker
+              key={`cluster-${cluster_id}`}
+              position={{ lat, lng }}
+              onClick={() => handleClusterClick(cluster_id, lng, lat)}
+              zIndex={100}
+            >
+              <div
+                style={{
+                  width: size,
+                  height: size,
+                  borderRadius: "50%",
+                  background: "linear-gradient(135deg, #E8720C 0%, #f59e0b 100%)",
+                  border: "3px solid #fff",
+                  boxShadow: "0 2px 8px rgba(0,0,0,0.25)",
+                  display: "flex",
+                  alignItems: "center",
+                  justifyContent: "center",
+                  color: "#fff",
+                  fontSize: size > 42 ? 15 : 13,
+                  fontWeight: 700,
+                  cursor: "pointer",
+                  transition: "transform 0.2s ease",
+                }}
+              >
+                {point_count}
+              </div>
+            </AdvancedMarker>
+          );
+        }
+
+        // Individual marker
+        const r = (feature.properties as { restaurant: Restaurant }).restaurant;
         const isSelected = selected?.id === r.id;
         const isClosed = r.business_status === "CLOSED_PERMANENTLY";
         const chKey = activeChannel && r.channels?.includes(activeChannel) ? activeChannel : r.channels?.[0];