fix: 刷新页面后恢复滑动进度，防止重复 swipe

服务端 GET room 返回 swipeCounts，前端据此恢复 currentIndex、
swipeHistory 和引导状态；swipe API 增加幂等性检查，跳过已滑过的卡片。

src/app/api/room/[id]/route.ts

@@ -51,6 +51,7 @@ export async function GET(
       matchType,
       matchLikes,
       likeCounts,
+      swipeCounts: data.swipeCounts,
       restaurants: data.restaurants,
     });
   } catch (e) {

src/app/api/room/[id]/swipe/route.ts

@@ -20,6 +20,13 @@ export async function POST(
     const rid = String(restaurantId);
 
     const updated = await atomicUpdateRoom(id, (data) => {
+      const restaurantIndex = data.restaurants.findIndex((r) => r.id === rid);
+      const alreadySwiped =
+        restaurantIndex >= 0 &&
+        restaurantIndex < (data.swipeCounts[userId] ?? 0);
+
+      if (alreadySwiped) return data;
+
       if (action === "like") {
         if (!data.likes[rid]) {
           data.likes[rid] = [];

src/app/room/[id]/page.tsx

@@ -15,7 +15,7 @@ export default function RoomPage() {
   const [joined, setJoined] = useState(false);
 
   const {
-    userCount, match, matchType, matchLikes, likeCounts, restaurants, mutate,
+    userCount, match, matchType, matchLikes, likeCounts, swipeCounts, restaurants, mutate,
   } = useRoomPolling(roomId);
 
   useEffect(() => {
@@ -34,6 +34,7 @@ export default function RoomPage() {
     await mutate();
   }, [roomId, mutate]);
 
+  const initialIndex = swipeCounts[userId] ?? 0;
   const ready = joined && userId && restaurants.length > 0;
 
   if (!ready) {
@@ -52,6 +53,7 @@ export default function RoomPage() {
         restaurants={restaurants}
         roomId={roomId}
         userId={userId}
+        initialIndex={initialIndex}
         matchedRestaurantId={match}
         matchType={matchType}
         matchLikes={matchLikes}