feat(ui): add ShareSheet component for multi-channel post sharing

Add ShareSheet component that provides native sharing options (WeChat, Moments, copy link, etc.) replacing the previous clipboard-only approach. Also change like icon from heart to thumb-up to better match the share functionality.

src/screens/home/HomeScreen.tsx

@@ -29,7 +29,7 @@ import { Post } from '../../types';
 import { useUserStore, useHomeTabBarVisibilityStore, useHomeTabPressStore } from '../../stores';
 import { useCurrentUser } from '../../stores/auth';
 import { channelService, postService } from '../../services';
-import { PostCard, TabBar, SearchBar } from '../../components/business';
+import { PostCard, TabBar, SearchBar, ShareSheet } from '../../components/business';
 import type { PostCardAction } from '../../components/business/PostCard';
 import { Loading, EmptyState, Text, ImageGallery, ImageGridItem, ResponsiveGrid } from '../../components/common';
 import { useResponsive, useResponsiveSpacing } from '../../hooks/useResponsive';
@@ -203,6 +203,10 @@ export const HomeScreen: React.FC = () => {
   // 发帖弹窗状态
   const [showCreatePost, setShowCreatePost] = useState(false);
 
+  // 分享面板状态
+  const [showShareSheet, setShowShareSheet] = useState(false);
+  const [sharePost, setSharePost] = useState<Post | null>(null);
+
   useEffect(() => {
     if (showCreatePost) {
       blurActiveElement();
@@ -576,20 +580,10 @@ export const HomeScreen: React.FC = () => {
     }
   };
 
-  // 分享帖子
-  const handleShare = async (post: Post) => {
-    if (!post?.id) return;
-    try {
-      const res = await postService.sharePost(post.id, { channel: 'copy_link' });
-      if (res.ok && res.shares_count != null) {
-        postSyncService.applyShareCountUpdate(post.id, res.shares_count);
-      }
-    } catch (shareError) {
-      console.error('上报分享次数失败:', shareError);
-    }
-    const postUrl = `https://browser.littlelan.cn/post/${encodeURIComponent(post.id)}`;
-    Clipboard.setString(postUrl);
-    Alert.alert('已复制', '帖子链接已复制到剪贴板');
+  // 分享帖子 - 打开分享面板
+  const handleShare = (post: Post) => {
+    setSharePost(post);
+    setShowShareSheet(true);
   };
 
   // 删除帖子 - 删除后刷新列表
@@ -1081,6 +1075,31 @@ export const HomeScreen: React.FC = () => {
           onClose={() => setShowCreatePost(false)}
         />
       </Modal>
+
+      {/* 分享面板 */}
+      <ShareSheet
+        visible={showShareSheet}
+        postUrl={sharePost ? `https://browser.littlelan.cn/post/${encodeURIComponent(sharePost.id)}` : undefined}
+        postTitle={sharePost?.title}
+        onClose={() => {
+          setShowShareSheet(false);
+          setSharePost(null);
+        }}
+        onShareAction={(actionKey) => {
+          if (sharePost) {
+            (async () => {
+              try {
+                const res = await postService.sharePost(sharePost.id, { channel: actionKey });
+                if (res.ok && res.shares_count != null) {
+                  postSyncService.applyShareCountUpdate(sharePost.id, res.shares_count);
+                }
+              } catch (e) {
+                console.error('上报分享次数失败:', e);
+              }
+            })();
+          }
+        }}
+      />
     </SafeAreaView>
   );
 };