refactor(ui): implement custom header system and unify screen layouts

Refactor the navigation and header strategy by replacing native stack headers with a custom `SimpleHeader` component across most profile and detail screens. This provides a more consistent UI/UX and better control over layout behavior.

- Implement `SimpleHeader` component in `src/components/common`.
- Disable native header rendering in `app/(app)/(tabs)/profile/_layout.tsx` and `app/_layout.tsx`.
- Update profile sub-screens to use `SimpleHeader` and `StatusBar` from `expo-status-bar`.
- Refactor `PostDetailScreen` to use a custom header implementation for better integration with the post author information.
- Update `UserScreen` to wrap content in `SafeAreaView` with the new header.
- Adjust `AppBackButton` to support transparent backgrounds.

src/screens/profile/SettingsScreen.tsx

@@ -13,6 +13,7 @@ import {
   ScrollView,
 } from 'react-native';
 import { SafeAreaView } from 'react-native-safe-area-context';
+import { StatusBar } from 'expo-status-bar';
 import { useRouter } from 'expo-router';
 import { MaterialCommunityIcons } from '@expo/vector-icons';
 import Constants from 'expo-constants';
@@ -26,7 +27,7 @@ import {
   type AppColors,
 } from '../../theme';
 import { useAuthStore } from '../../stores';
-import { Text } from '../../components/common';
+import { Text, SimpleHeader } from '../../components/common';
 import { useResponsive, useResponsiveSpacing } from '../../hooks';
 import { useSafeAreaInsets } from 'react-native-safe-area-context';
 import * as hrefs from '../../navigation/hrefs';
@@ -365,7 +366,9 @@ export const SettingsScreen: React.FC = () => {
   );
 
   return (
-    <SafeAreaView style={styles.container} edges={['bottom']}>
+    <SafeAreaView style={styles.container} edges={['top', 'bottom']}>
+      <StatusBar style="auto" />
+      <SimpleHeader title="设置" onBack={() => router.back()} />
       <ScrollView contentContainerStyle={[styles.scrollContent, { paddingBottom: scrollBottomInset, paddingHorizontal: responsivePadding }]}>
         {renderContent()}
       </ScrollView>