Refactor: Remove background task management and related hooks

- Deleted `useBackgroundTasks.ts` hook and its associated logic for managing background tasks.
- Removed `backgroundTaskManager.ts` service and all related task definitions and registrations.
- Cleaned up `Podfile.lock` and `package.json` to remove unused dependencies related to background tasks.
- Updated iOS project files to eliminate references to removed background task components.
- Added new background fetch identifier in `Info.plist` for future use.

app/(tabs)/statistics.tsx

@@ -13,9 +13,7 @@ import { Colors } from '@/constants/Colors';
 import { getTabBarBottomPadding } from '@/constants/TabBar';
 import { useAppDispatch, useAppSelector } from '@/hooks/redux';
 import { useAuthGuard } from '@/hooks/useAuthGuard';
-import { useBackgroundTasks } from '@/hooks/useBackgroundTasks';
 import { notificationService } from '@/services/notifications';
-import { backgroundTaskManager } from '@/services/backgroundTaskManager';
 import { selectHealthDataByDate, setHealthData } from '@/store/healthSlice';
 import { fetchDailyMoodCheckins, selectLatestMoodRecordByDate } from '@/store/moodSlice';
 import { fetchDailyNutritionData, selectNutritionSummaryByDate } from '@/store/nutritionSlice';
@@ -38,8 +36,8 @@ import {
   ScrollView,
   StyleSheet,
   Text,
-  View,
-  TouchableOpacity
+  TouchableOpacity,
+  View
 } from 'react-native';
 import { useSafeAreaInsets } from 'react-native-safe-area-context';
 
@@ -150,7 +148,6 @@ export default function ExploreScreen() {
     });
   }, [userProfile]);
 
-  const { registerTask, isInitialized } = useBackgroundTasks();
   // 心情相关状态
   const dispatch = useAppDispatch();
   const [isMoodLoading, setIsMoodLoading] = useState(false);
@@ -416,49 +413,6 @@ export default function ExploreScreen() {
     };
   }, [loadAllData, currentSelectedDate]);
 
-  useEffect(() => {
-    // 只有在后台任务管理器初始化完成后才注册任务
-    if (isInitialized) {
-      console.log('后台任务管理器已初始化，开始注册健康数据任务...');
-      registerTask({
-        id: 'health-data-task',
-        name: 'health-data-task',
-        handler: async () => {
-          try {
-            console.log('后台任务：更新健康数据和检查压力水平...');
-
-            // 发送测试通知，验证后台任务是否执行
-            await notificationService.sendImmediateNotification({
-              title: '后台任务测试 🔔',
-              body: `任务执行时间: ${new Date().toLocaleTimeString('zh-CN')}`,
-              data: {
-                type: 'background_task_test',
-                timestamp: new Date().toISOString(),
-              },
-              sound: true,
-              priority: 'high'
-            });
-
-            // 后台任务只更新健康数据，强制刷新以获取最新数据
-            await loadHealthData(undefined, true);
-
-            // 执行压力检查
-            await checkStressLevelAndNotify();
-
-            // 执行喝水目标检查
-            await checkWaterGoalAndNotify();
-          } catch (error) {
-            console.error('健康数据任务执行失败:', error);
-          }
-        },
-      }).then(() => {
-        console.log('健康数据任务注册成功');
-      }).catch((error) => {
-        console.error('健康数据任务注册失败:', error);
-      });
-    }
-  }, [isInitialized]);
-
   // 检查压力水平并发送通知
   const checkStressLevelAndNotify = React.useCallback(async () => {
     try {
@@ -627,7 +581,7 @@ export default function ExploreScreen() {
                 style={styles.debugButton}
                 onPress={async () => {
                   console.log('🔧 手动触发后台任务测试...');
-                  await backgroundTaskManager.debugExecuteBackgroundTask();
+                  // await backgroundTaskManager.triggerTaskForTesting();
                 }}
               >
                 <Text style={styles.debugButtonText}>🔧</Text>