feat(vip): 实现VIP服务权限控制和食物识别功能限制

- 添加VIP服务权限检查hook，支持免费使用次数限制
- 为食物识别功能添加登录验证和VIP权限检查
- 优化RevenueCat用户标识同步逻辑
- 修复会员购买状态检查的类型安全问题
- 为营养成分分析添加登录验证

app/food/food-recognition.tsx

@@ -1,8 +1,11 @@
 import { HeaderBar } from '@/components/ui/HeaderBar';
 import { Colors } from '@/constants/Colors';
+import { useMembershipModal } from '@/contexts/MembershipModalContext';
 import { useAppDispatch } from '@/hooks/redux';
+import { useAuthGuard } from '@/hooks/useAuthGuard';
 import { useCosUpload } from '@/hooks/useCosUpload';
 import { useSafeAreaTop } from '@/hooks/useSafeAreaWithPadding';
+import { useVipService } from '@/hooks/useVipService';
 import { recognizeFood } from '@/services/foodRecognition';
 import { saveRecognitionResult, setError, setLoading } from '@/store/foodRecognitionSlice';
 import { Ionicons } from '@expo/vector-icons';
@@ -37,6 +40,11 @@ export default function FoodRecognitionScreen() {
   const [currentStep, setCurrentStep] = useState<'idle' | 'uploading' | 'recognizing' | 'completed' | 'failed'>('idle');
   const dispatch = useAppDispatch();
 
+  // 添加认证和VIP服务相关hooks
+  const { ensureLoggedIn } = useAuthGuard();
+  const { handleServiceAccess } = useVipService();
+  const { openMembershipModal } = useMembershipModal();
+
   // 动画引用
   const scaleAnim = useRef(new Animated.Value(1)).current;
   const fadeAnim = useRef(new Animated.Value(0)).current;
@@ -125,6 +133,28 @@ export default function FoodRecognitionScreen() {
       })
     ]).start();
 
+    // 先验证登录状态
+    const isLoggedIn = await ensureLoggedIn();
+    if (!isLoggedIn) {
+      return;
+    }
+
+    // 检查用户是否可以使用 AI 食物识别功能
+    const canAccess = handleServiceAccess(
+      () => {
+        // 允许使用，继续执行识别流程
+      },
+      () => {
+        // 不允许使用，显示会员付费弹窗
+        openMembershipModal();
+      }
+    );
+
+    // 如果用户没有权限，直接返回
+    if (!canAccess) {
+      return;
+    }
+
     try {
       setShowRecognitionProcess(true);
       setRecognitionLogs([]);