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/components/SwipeDeck.tsx

@@ -13,6 +13,7 @@ interface SwipeDeckProps {
   restaurants: Restaurant[];
   roomId: string;
   userId: string;
+  initialIndex: number;
   matchedRestaurantId: string | null;
   matchType: MatchType;
   matchLikes: number;
@@ -25,6 +26,7 @@ export default function SwipeDeck({
   restaurants,
   roomId,
   userId,
+  initialIndex,
   matchedRestaurantId,
   matchType,
   matchLikes,
@@ -32,13 +34,15 @@ export default function SwipeDeck({
   userCount,
   onReset,
 }: SwipeDeckProps) {
-  const [currentIndex, setCurrentIndex] = useState(0);
+  const [currentIndex, setCurrentIndex] = useState(initialIndex);
   const [showMatch, setShowMatch] = useState(false);
   const [localMatchId, setLocalMatchId] = useState<string | null>(null);
   const [resetting, setResetting] = useState(false);
   const [bubble, setBubble] = useState("");
-  const [guideVisible, setGuideVisible] = useState(true);
-  const [swipeHistory, setSwipeHistory] = useState<string[]>([]);
+  const [guideVisible, setGuideVisible] = useState(initialIndex === 0);
+  const [swipeHistory, setSwipeHistory] = useState<string[]>(
+    () => restaurants.slice(0, initialIndex).map((r) => r.id),
+  );
   const swipeFnRef = useRef<((direction: SwipeDirection) => void) | null>(null);
   const swipingRef = useRef(false);
   const prevLikeCounts = useRef<Record<string, number>>({});