支持公开用户主页、帖子图缩略图与编辑器图组排版。

新增用户签名与活动统计、图片灯箱；正文按需生成缩略图；TipTap 支持多图分组与环绕排版，并注入站点标题避免刷新闪烁。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/App.tsx

@@ -22,6 +22,7 @@ const RegisterPage = lazy(() => import('./pages/RegisterPage'));
 const ComposePage = lazy(() => import('./pages/ComposePage'));
 const BoardsManagePage = lazy(() => import('./pages/BoardsManagePage'));
 const ProfilePage = lazy(() => import('./pages/ProfilePage'));
+const UserProfilePage = lazy(() => import('./pages/UserProfilePage'));
 const FavoritesPage = lazy(() => import('./pages/FavoritesPage'));
 const ProjectsPage = lazy(() => import('./pages/ProjectsPage'));
 const AdminDashboardPage = lazy(() => import('./pages/admin/AdminDashboardPage'));
@@ -51,6 +52,7 @@ const router = createBrowserRouter(
         <Route path="/post/:id/edit" element={<ComposePage />} />
         <Route path="/compose" element={<ComposePage />} />
         <Route path="/profile" element={<ProfilePage />} />
+        <Route path="/user/:id" element={<UserProfilePage />} />
         <Route path="/favorites" element={<FavoritesPage />} />
         <Route path="/projects" element={<ProjectsPage />} />
       </Route>