feat(ProcessPostUseCase, HomeScreen, PostDetailScreen, PostService): implement share count synchronization after post sharing

- Added applyShareCountUpdate method in ProcessPostUseCase to synchronize share counts across post lists and details.
- Updated sharePost method in PostService to return the latest shares_count from the server.
- Modified share handling in HomeScreen and PostDetailScreen to utilize the new share count synchronization logic after a successful share operation.
- Enhanced error handling for share operations to improve user feedback.

src/screens/home/HomeScreen.tsx

@@ -336,7 +336,10 @@ export const HomeScreen: React.FC = () => {
   const handleShare = async (post: Post) => {
     if (!post?.id) return;
     try {
-      await postService.sharePost(post.id);
+      const res = await postService.sharePost(post.id, { channel: 'copy_link' });
+      if (res.ok && res.shares_count != null) {
+        processPostUseCase.applyShareCountUpdate(post.id, res.shares_count);
+      }
     } catch (shareError) {
       console.error('上报分享次数失败:', shareError);
     }

src/screens/home/PostDetailScreen.tsx

@@ -514,7 +514,15 @@ export const PostDetailScreen: React.FC = () => {
   const handleShare = useCallback(async () => {
     if (!post?.id) return;
     try {
-      await postService.sharePost(post.id);
+      const res = await postService.sharePost(post.id, { channel: 'copy_link' });
+      if (res.ok && res.shares_count != null) {
+        setPost((prev) =>
+          prev
+            ? { ...prev, shares_count: res.shares_count!, sharesCount: res.shares_count! }
+            : null
+        );
+        processPostUseCase.applyShareCountUpdate(post.id, res.shares_count);
+      }
     } catch (error) {
       console.error('上报分享次数失败:', error);
     }