feat(auth): 添加登录验证到食物记录相关功能

- 在食物拍照、语音记录和营养成分分析功能中添加登录验证
- 使用 ensureLoggedIn 方法确保用户已登录后再调用服务端接口
- 使用 pushIfAuthedElseLogin 方法处理需要登录的页面导航
- 添加新的营养图标资源
- 在路由常量中添加 FOOD_CAMERA 路由定义
- 更新 Memory Bank 任务文档，记录登录验证和路由常量管理的实现模式

app/food/nutrition-label-analysis.tsx

@@ -1,5 +1,6 @@
 import { HeaderBar } from '@/components/ui/HeaderBar';
 import { Colors } from '@/constants/Colors';
+import { useAuthGuard } from '@/hooks/useAuthGuard';
 import { useCosUpload } from '@/hooks/useCosUpload';
 import { useSafeAreaTop } from '@/hooks/useSafeAreaWithPadding';
 import {
@@ -30,6 +31,7 @@ import ImageViewing from 'react-native-image-viewing';
 export default function NutritionLabelAnalysisScreen() {
   const safeAreaTop = useSafeAreaTop();
   const router = useRouter();
+  const { pushIfAuthedElseLogin, ensureLoggedIn } = useAuthGuard();
   const { upload, uploading: uploadingToCos, progress: uploadProgress } = useCosUpload({
     prefix: 'nutrition-labels'
   });
@@ -186,7 +188,7 @@ export default function NutritionLabelAnalysisScreen() {
         right={
           isLiquidGlassAvailable() ? (
             <TouchableOpacity
-              onPress={() => router.push('/food/nutrition-analysis-history')}
+              onPress={() => pushIfAuthedElseLogin('/food/nutrition-analysis-history')}
               activeOpacity={0.7}
             >
               <GlassView
@@ -200,7 +202,7 @@ export default function NutritionLabelAnalysisScreen() {
             </TouchableOpacity>
           ) : (
             <TouchableOpacity
-              onPress={() => router.push('/food/nutrition-analysis-history')}
+              onPress={() => pushIfAuthedElseLogin('/food/nutrition-analysis-history')}
               style={[styles.historyButton, styles.fallbackBackground]}
               activeOpacity={0.7}
             >
@@ -241,7 +243,13 @@ export default function NutritionLabelAnalysisScreen() {
               {!isAnalyzing && !isUploading && !newAnalysisResult && (
                 <TouchableOpacity
                   style={styles.analyzeButton}
-                  onPress={() => startNewAnalysis(imageUri)}
+                  onPress={async () => {
+                    // 先验证登录状态
+                    const isLoggedIn = await ensureLoggedIn();
+                    if (isLoggedIn) {
+                      startNewAnalysis(imageUri);
+                    }
+                  }}
                   activeOpacity={0.8}
                 >
                   <Ionicons name="search-outline" size={20} color="#FFF" />