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/PostDetailScreen.tsx

@@ -39,7 +39,7 @@ import { useCurrentUser } from '../../stores/auth';
 import { postService, commentService, uploadService, authService, showPrompt, voteService } from '../../services';
 import { postSyncService } from '@/services/post';
 import { useCursorPagination } from '../../hooks/useCursorPagination';
-import { CommentItem, VoteCard, ReportDialog } from '../../components/business';
+import { CommentItem, VoteCard, ReportDialog, ShareSheet } from '../../components/business';
 import { Avatar, Button, Loading, EmptyState, Text, ImageGallery, ImageGrid, ImageGridItem, AdaptiveLayout, AppBackButton } from '../../components/common';
 import { useResponsive, useResponsiveValue, useResponsiveSpacing } from '../../hooks/useResponsive';
 import { handleError } from '@/services/core';
@@ -207,6 +207,9 @@ export const PostDetailScreen: React.FC = () => {
   // 举报相关状态
   const [reportDialogVisible, setReportDialogVisible] = useState(false);
   const [reportTarget, setReportTarget] = useState<{ type: 'post' | 'comment'; id: string } | null>(null);
+
+  // 分享面板状态
+  const [shareSheetVisible, setShareSheetVisible] = useState(false);
   
   // 投票相关状态
   const [voteResult, setVoteResult] = useState<VoteResultDTO | null>(null);
@@ -515,25 +518,10 @@ export const PostDetailScreen: React.FC = () => {
     }
   }, [post]);
 
-  // 分享帖子
+  // 分享帖子 - 打开分享面板
   const handleShare = useCallback(async () => {
     if (!post?.id) return;
-    try {
-      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
-        );
-        postSyncService.applyShareCountUpdate(post.id, res.shares_count);
-      }
-    } catch (error) {
-      console.error('上报分享次数失败:', error);
-    }
-    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');
+    setShareSheetVisible(true);
   }, [post?.id]);
 
   // 投票处理函数
@@ -1757,6 +1745,35 @@ export const PostDetailScreen: React.FC = () => {
           setReportTarget(null);
         }}
       />
+
+      {/* 分享面板 */}
+      <ShareSheet
+        visible={shareSheetVisible}
+        postUrl={post ? `https://browser.littlelan.cn/post/${encodeURIComponent(post.id)}` : undefined}
+        postTitle={post?.title}
+        onClose={() => {
+          setShareSheetVisible(false);
+        }}
+        onShareAction={(actionKey) => {
+          if (post) {
+            (async () => {
+              try {
+                const res = await postService.sharePost(post.id, { channel: actionKey });
+                if (res.ok && res.shares_count != null) {
+                  setPost((prev) =>
+                    prev
+                      ? { ...prev, shares_count: res.shares_count!, sharesCount: res.shares_count! }
+                      : null
+                  );
+                  postSyncService.applyShareCountUpdate(post.id, res.shares_count!);
+                }
+              } catch (error) {
+                console.error('上报分享次数失败:', error);
+              }
+            })();
+          }
+        }}
+      />
     </View>
   );
 };
@@ -1982,18 +1999,14 @@ function createPostDetailStyles(colors: AppColors) {
   commentSectionCount: {
     marginLeft: spacing.xs,
     fontSize: fontSizes.sm,
+    color: colors.text.hint,
   },
   commentSectionUnderline: {
     width: 28,
     height: 3,
     backgroundColor: colors.text.primary,
     marginTop: spacing.xs,
-    borderRadius: borderRadius.xs,
-  },
-  commentSectionCount: {
-    marginLeft: spacing.xs,
-    fontSize: fontSizes.sm,
-    color: colors.text.hint,
+    borderRadius: borderRadius.sm,
   },
   inputContainer: {
     backgroundColor: colors.background.paper,
@@ -2179,7 +2192,7 @@ function createPostDetailStyles(colors: AppColors) {
     height: 20,
     backgroundColor: colors.background.disabled,
     margin: 2,
-    borderRadius: borderRadius.xs,
+    borderRadius: borderRadius.sm,
   },
   emptyCommentsGridItemActive: {
     backgroundColor: colors.text.hint,