feat: 实时消息与管理端运营能力

新增群聊/私信与公共 WebSocket 总线，站长用户内容档案，并将通知与待审角标改为推送驱动；同步精简管理仪表盘并修复主题换肤 DOM 冲突。

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

frontend/app/page.tsx

@@ -12,6 +12,7 @@ import { getMeCached } from "@/lib/serverData";
 import Pagination from "@/components/Pagination";
 import PostRow from "@/components/PostRow";
 import FeedTabs, { type FeedSort } from "@/components/home/FeedTabs";
+import FeedNewTip from "@/components/home/FeedNewTip";
 import { WorkspaceNav, WorkspaceNavMobile } from "@/components/home/WorkspaceNav";
 import { CommunityPanels, CommunityPanelsMobile } from "@/components/home/CommunityPanels";
 
@@ -158,6 +159,14 @@ export default async function HomePage({ searchParams }: HomePageProps) {
                 共 {postsData.total} 篇
               </span>
             </div>
+            {user && (
+              <FeedNewTip
+                sort={sort}
+                boardId={boardId}
+                page={page}
+                userId={user.id}
+              />
+            )}
             {postsData.posts.length > 0 ? (
               postsData.posts.map((post, i) => (
                 <PostRow