fix: 연관 선박 위치 live fallback — 트랙 데이터 없을 때 ships 배열 사용

- useGearReplayLayers에 shipsRef 파라미터 추가
- corrPositions 계산: 트랙 보간 우선 → live 선박 위치 fallback
- KoreaMap: allShips → shipsRef에 매 렌더 동기화 (ref로 re-render 방지)
- globalThis.Map으로 react-map-gl Map 타입 충돌 해결

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/korea/KoreaMap.tsx

@@ -238,13 +238,21 @@ export function KoreaMap({ ships, allShips, aircraft, satellites, layers, osintF
 
   // ── deck.gl 리플레이 레이어 (Zustand → imperative setProps, React 렌더 우회) ──
   const reactLayersRef = useRef<DeckLayer[]>([]);
+  type ShipPos = { lng: number; lat: number; course?: number };
+  const shipsRef = useRef(new globalThis.Map<string, ShipPos>());
+  // live 선박 위치를 ref에 동기화 (리플레이 fallback용)
+  const allShipsList = allShips ?? ships;
+  const shipPosMap = new globalThis.Map<string, ShipPos>();
+  for (const s of allShipsList) shipPosMap.set(s.mmsi, { lng: s.lng, lat: s.lat, course: s.course });
+  shipsRef.current = shipPosMap;
+
   const requestRender = useCallback(() => {
     if (!overlayRef.current) return;
     overlayRef.current.setProps({
       layers: [...reactLayersRef.current, ...replayLayerRef.current],
     });
   }, []);
-  useGearReplayLayers(replayLayerRef, requestRender);
+  useGearReplayLayers(replayLayerRef, requestRender, shipsRef);
 
   useEffect(() => {
     fetchKoreaInfra().then(setInfra).catch(() => {});

frontend/src/hooks/useGearReplayLayers.ts

@@ -52,6 +52,7 @@ interface CorrPosition {
 export function useGearReplayLayers(
   replayLayerRef: React.MutableRefObject<Layer[]>,
   requestRender: () => void,
+  shipsRef: React.MutableRefObject<Map<string, { lng: number; lat: number; course?: number }>>,
 ): void {
   // ── React selectors (infrequent changes only) ────────────────────────────
   const historyFrames = useGearReplayStore(s => s.historyFrames);
@@ -263,9 +264,10 @@ export function useGearReplayLayers(
       }));
     }
 
-    // 6. Correlation vessel positions (interpolated from correlationTripsData)
+    // 6. Correlation vessel positions (트랙 보간 우선, 없으면 live 위치 fallback)
     const corrPositions: CorrPosition[] = [];
     const corrTrackMap = new Map(correlationTripsData.map(d => [d.id, d]));
+    const liveShips = shipsRef.current;
 
     for (const [mn, items] of correlationByModel) {
       if (!enabledModels.has(mn)) continue;
@@ -275,29 +277,43 @@ export function useGearReplayLayers(
       for (const c of items as GearCorrelationItem[]) {
         if (corrPositions.some(p => p.mmsi === c.targetMmsi)) continue;
 
+        let lon: number | undefined;
+        let lat: number | undefined;
+        let cog = 0;
+
+        // 방법 1: 트랙 데이터 보간
         const tripData = corrTrackMap.get(c.targetMmsi);
-        if (!tripData) continue;
-
-        const relTime = ct - st;
-        const ts = tripData.timestamps;
-        const path = tripData.path;
-        if (ts.length === 0) continue;
-        if (relTime < ts[0] || relTime > ts[ts.length - 1]) continue;
-
-        // Binary search in timestamps
-        let lo = 0;
-        let hi = ts.length - 1;
-        while (lo < hi - 1) {
-          const mid = (lo + hi) >> 1;
-          if (ts[mid] <= relTime) lo = mid; else hi = mid;
+        if (tripData && tripData.timestamps.length > 0) {
+          const relTime = ct - st;
+          const ts = tripData.timestamps;
+          const path = tripData.path;
+          if (relTime >= ts[0] && relTime <= ts[ts.length - 1]) {
+            let lo = 0;
+            let hi = ts.length - 1;
+            while (lo < hi - 1) {
+              const mid = (lo + hi) >> 1;
+              if (ts[mid] <= relTime) lo = mid; else hi = mid;
+            }
+            const ratio = ts[hi] !== ts[lo] ? (relTime - ts[lo]) / (ts[hi] - ts[lo]) : 0;
+            lon = path[lo][0] + (path[hi][0] - path[lo][0]) * ratio;
+            lat = path[lo][1] + (path[hi][1] - path[lo][1]) * ratio;
+            const dx = path[hi][0] - path[lo][0];
+            const dy = path[hi][1] - path[lo][1];
+            cog = (dx === 0 && dy === 0) ? 0 : (Math.atan2(dx, dy) * 180 / Math.PI + 360) % 360;
+          }
         }
-        const ratio = ts[hi] !== ts[lo] ? (relTime - ts[lo]) / (ts[hi] - ts[lo]) : 0;
-        const lon = path[lo][0] + (path[hi][0] - path[lo][0]) * ratio;
-        const lat = path[lo][1] + (path[hi][1] - path[lo][1]) * ratio;
-        // heading from segment direction
-        const dx = path[hi][0] - path[lo][0];
-        const dy = path[hi][1] - path[lo][1];
-        const cog = (dx === 0 && dy === 0) ? 0 : (Math.atan2(dx, dy) * 180 / Math.PI + 360) % 360;
+
+        // 방법 2: live 선박 위치 fallback
+        if (lon === undefined) {
+          const ship = liveShips.get(c.targetMmsi);
+          if (ship) {
+            lon = ship.lng;
+            lat = ship.lat;
+            cog = ship.course ?? 0;
+          }
+        }
+
+        if (lon === undefined || lat === undefined) continue;
 
         corrPositions.push({
           mmsi: c.targetMmsi,