refactor(PostCard, PostCard.legacy): remove legacy PostCard component and update exports

- Deleted the legacy PostCard component to streamline the codebase and improve maintainability.
- Updated exports in PostCard and index files to remove references to the legacy component.
- Adjusted PostCardProps to eliminate legacy properties, ensuring only the new API is supported.
- Enhanced the PostCard component to focus on modern implementation and features.

src/screens/home/PostDetailScreen.tsx

@@ -281,8 +281,25 @@ export const PostDetailScreen: React.FC = () => {
     if (!post?.author) return;
     
     const author = post.author;
+    const handleBackPress = () => {
+      if (navigation.canGoBack()) {
+        navigation.goBack();
+        return;
+      }
+      navigation.navigate('Main', {
+        screen: 'HomeTab',
+        params: { screen: 'Home', params: undefined },
+      });
+    };
     
     navigation.setOptions({
+      headerBackVisible: false,
+      headerTitleAlign: 'left',
+      headerLeft: () => (
+        <TouchableOpacity onPress={handleBackPress} style={styles.headerBackButton} hitSlop={8}>
+          <MaterialCommunityIcons name="arrow-left" size={24} color={colors.text.primary} />
+        </TouchableOpacity>
+      ),
       headerTitle: () => (
         <View style={styles.headerContainer}>
           <TouchableOpacity
@@ -298,7 +315,9 @@ export const PostDetailScreen: React.FC = () => {
           <View style={styles.headerUserInfo}>
             <TouchableOpacity onPress={() => handleUserPress(author.id)}>
               <Text style={styles.headerNickname} numberOfLines={1}>
-                {author.nickname}
+                {author.nickname && author.nickname.length > 10
+                  ? `${author.nickname.slice(0, 10)}...`
+                  : author.nickname}
               </Text>
             </TouchableOpacity>
           </View>
@@ -1701,7 +1720,7 @@ const styles = StyleSheet.create({
     flexDirection: 'row',
     alignItems: 'center',
     flex: 1,
-    marginLeft: -8,
+    marginLeft: spacing.sm,
   },
   headerAvatarWrapper: {
     marginRight: spacing.sm,
@@ -1720,6 +1739,12 @@ const styles = StyleSheet.create({
     alignItems: 'center',
     marginRight: spacing.sm,
   },
+  headerBackButton: {
+    paddingHorizontal: spacing.xs,
+    paddingVertical: spacing.xs,
+    marginLeft: spacing.xs,
+    marginRight: spacing.sm,
+  },
   // 帖子容器
   postContainer: {
     backgroundColor: colors.background.paper,