feat: 新用户滑动引导，首次进入展示手势提示

- 首张卡片叠加半透明引导层，左滑不想去/右滑想去动画提示
- 支持点击消失、拖拽消失、3秒自动消失
- localStorage 记录标记，每个用户只展示一次
- 修复 React Strict Mode 下 effect 双执行导致引导不显示的问题

src/components/SwipeDeck.tsx

@@ -5,6 +5,7 @@ import { AnimatePresence, motion } from "framer-motion";
 import SwipeableCard from "./SwipeableCard";
 import ActionButtons from "./ActionButtons";
 import MatchResult from "./MatchResult";
+import SwipeGuide from "./SwipeGuide";
 import { Restaurant, SwipeDirection, MatchType } from "@/types";
 import { Heart } from "lucide-react";
 
@@ -36,6 +37,7 @@ export default function SwipeDeck({
   const [localMatchId, setLocalMatchId] = useState<string | null>(null);
   const [resetting, setResetting] = useState(false);
   const [bubble, setBubble] = useState("");
+  const [guideVisible, setGuideVisible] = useState(true);
   const swipeFnRef = useRef<((direction: SwipeDirection) => void) | null>(null);
   const swipingRef = useRef(false);
   const prevLikeCounts = useRef<Record<string, number>>({});
@@ -97,6 +99,7 @@ export default function SwipeDeck({
       if (!current) return;
 
       swipingRef.current = false;
+      if (guideVisible) setGuideVisible(false);
 
       const action = direction === "right" ? "like" : "nope";
       sendSwipe(current.id, action);
@@ -163,6 +166,9 @@ export default function SwipeDeck({
 
       <div className="relative flex flex-1 items-center justify-center px-4">
         <div className="relative h-[70vh] w-full max-w-sm">
+          {currentIndex === 0 && !resolvedMatchId && guideVisible && (
+            <SwipeGuide onDismiss={() => setGuideVisible(false)} />
+          )}
           {!resolvedMatchId && (
             <AnimatePresence>
               {restaurants.map((restaurant, index) => {

src/components/SwipeGuide.tsx

@@ -0,0 +1,97 @@
+"use client";
+
+import { useEffect, useState, useCallback } from "react";
+import { motion, AnimatePresence } from "framer-motion";
+import { ThumbsDown, ThumbsUp } from "lucide-react";
+
+const STORAGE_KEY = "nw_guide_v2";
+
+interface SwipeGuideProps {
+  onDismiss: () => void;
+}
+
+export default function SwipeGuide({ onDismiss }: SwipeGuideProps) {
+  const [visible, setVisible] = useState(() => {
+    if (typeof window === "undefined") return false;
+    return !localStorage.getItem(STORAGE_KEY);
+  });
+
+  const dismiss = useCallback(() => {
+    setVisible(false);
+    localStorage.setItem(STORAGE_KEY, "1");
+    onDismiss();
+  }, [onDismiss]);
+
+  useEffect(() => {
+    if (!visible) {
+      onDismiss();
+      return;
+    }
+
+    const timer = setTimeout(dismiss, 3000);
+    return () => clearTimeout(timer);
+  }, []); // eslint-disable-line react-hooks/exhaustive-deps
+
+  return (
+    <AnimatePresence>
+      {visible && (
+        <motion.div
+          className="absolute inset-0 z-20 flex items-center justify-center rounded-2xl bg-black/50 backdrop-blur-[2px]"
+          initial={{ opacity: 0 }}
+          animate={{ opacity: 1 }}
+          exit={{ opacity: 0 }}
+          transition={{ duration: 0.25 }}
+          onClick={dismiss}
+          onTouchStart={dismiss}
+        >
+          <div className="flex w-full items-center justify-between px-8">
+            <motion.div
+              className="flex flex-col items-center gap-2"
+              initial={{ x: 0 }}
+              animate={{ x: [0, -24, 0] }}
+              transition={{ duration: 1.2, repeat: Infinity, ease: "easeInOut" }}
+            >
+              <div className="flex h-14 w-14 items-center justify-center rounded-full bg-rose-500/80">
+                <ThumbsDown size={26} className="text-white" />
+              </div>
+              <span className="text-sm font-bold text-white">不想去</span>
+              <span className="text-[10px] text-white/60">← 左滑</span>
+            </motion.div>
+
+            <motion.div
+              className="flex flex-col items-center gap-1"
+              initial={{ opacity: 0, scale: 0.8 }}
+              animate={{ opacity: 1, scale: 1 }}
+              transition={{ delay: 0.2 }}
+            >
+              <motion.div
+                className="h-8 w-0.5 rounded-full bg-white/30"
+                animate={{ scaleY: [1, 0.6, 1] }}
+                transition={{ duration: 1.5, repeat: Infinity }}
+              />
+              <span className="text-[10px] font-medium text-white/40">滑动卡片</span>
+              <motion.div
+                className="h-8 w-0.5 rounded-full bg-white/30"
+                animate={{ scaleY: [0.6, 1, 0.6] }}
+                transition={{ duration: 1.5, repeat: Infinity }}
+              />
+            </motion.div>
+
+            <motion.div
+              className="flex flex-col items-center gap-2"
+              initial={{ x: 0 }}
+              animate={{ x: [0, 24, 0] }}
+              transition={{ duration: 1.2, repeat: Infinity, ease: "easeInOut" }}
+            >
+              <div className="flex h-14 w-14 items-center justify-center rounded-full bg-emerald-500/80">
+                <ThumbsUp size={26} className="text-white" />
+              </div>
+              <span className="text-sm font-bold text-white">想去</span>
+              <span className="text-[10px] text-white/60">右滑 →</span>
+            </motion.div>
+          </div>
+        </motion.div>
+      )}
+    </AnimatePresence>
+  );
+}