Refactor components and enhance background task management

- Updated font sizes and weights in BasalMetabolismCard, MoodCard, HealthDataCard, and NutritionRadarCard for improved readability.
- Removed loading state from MoodCard to simplify the component.
- Adjusted styles in WeightHistoryCard for better layout and spacing.
- Integrated expo-background-fetch for improved background task handling.
- Updated Info.plist to include background fetch capability.
- Enhanced background task registration and execution logic in backgroundTaskManager.
- Added debug function to manually trigger background task execution for testing purposes.

hooks/useBackgroundTasks.ts

@@ -1,4 +1,5 @@
 import { BackgroundTaskType as BackgroundTask, backgroundTaskManager, TaskStatusType as TaskStatus } from '@/services/backgroundTaskManager';
+import * as BackgroundFetch from 'expo-background-fetch';
 import { useCallback, useEffect, useState } from 'react';
 
 export interface UseBackgroundTasksReturn {
@@ -16,7 +17,7 @@ export interface UseBackgroundTasksReturn {
   cleanupTaskStatuses: () => Promise<void>;
   
   // 后台任务状态
-  backgroundTaskStatus: string | null;
+  backgroundTaskStatus: BackgroundFetch.BackgroundFetchStatus | null;
   getBackgroundTaskStatus: () => Promise<void>;
 }
 
@@ -24,7 +25,7 @@ export const useBackgroundTasks = (): UseBackgroundTasksReturn => {
   const [isInitialized, setIsInitialized] = useState(false);
   const [taskStatuses, setTaskStatuses] = useState<TaskStatus[]>([]);
   const [registeredTasks, setRegisteredTasks] = useState<BackgroundTask[]>([]);
-  const [backgroundTaskStatus, setBackgroundTaskStatus] = useState<string | null>(null);
+  const [backgroundTaskStatus, setBackgroundTaskStatus] = useState<BackgroundFetch.BackgroundFetchStatus | null>(null);
 
   // 初始化
   useEffect(() => {
@@ -87,7 +88,7 @@ export const useBackgroundTasks = (): UseBackgroundTasksReturn => {
   const getBackgroundTaskStatus = useCallback(async () => {
     try {
       const status = await backgroundTaskManager.getBackgroundTaskStatus();
-      setBackgroundTaskStatus(status ? status.toString() : null);
+      setBackgroundTaskStatus(status);
     } catch (error) {
       console.error('获取后台任务状态失败:', error);
     }