fix: 添加删除帖子的 mock handler

- 支持 DELETE /api/posts/:postId 请求
- 从内存存储中正确删除评论
- 修复 mock 模式下删除评论失败的问题

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/mocks/handlers/event.js

@@ -1541,4 +1541,45 @@ export const eventHandlers = [
             );
         }
     }),
+
+    // 删除帖子/评论
+    http.delete('/api/posts/:postId', async ({ params }) => {
+        await delay(300);
+        const { postId } = params;
+
+        console.log('[Mock] 删除帖子, postId:', postId);
+
+        try {
+            // 从内存存储中删除评论
+            let deleted = false;
+            for (const [eventId, comments] of eventCommentsStore.entries()) {
+                const index = comments.findIndex(c => String(c.id) === String(postId));
+                if (index !== -1) {
+                    comments.splice(index, 1);
+                    deleted = true;
+                    console.log('[Mock] 评论已从事件', eventId, '中删除');
+                    break;
+                }
+            }
+
+            if (!deleted) {
+                console.log('[Mock] 未找到评论，但仍返回成功（可能是乐观更新的评论）');
+            }
+
+            return HttpResponse.json({
+                success: true,
+                message: '删除成功',
+            });
+        } catch (error) {
+            console.error('[Mock] 删除帖子失败:', error);
+            return HttpResponse.json(
+                {
+                    success: false,
+                    error: '删除失败',
+                    message: '系统错误，请稍后重试',
+                },
+                { status: 500 }
+            );
+        }
+    }),
 ];