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] = [];