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.

components/BasalMetabolismCard.tsx

@@ -133,14 +133,13 @@ const styles = StyleSheet.create({
     zIndex: 1,
   },
   value: {
-    fontSize: 24,
-    fontWeight: '800',
+    fontSize: 16,
+    fontWeight: '600',
     color: '#0F172A',
     lineHeight: 28,
   },
   unit: {
-    fontSize: 14,
-    fontWeight: '500',
+    fontSize: 12,
     color: '#64748B',
     marginLeft: 6,
   },