feat(admin): 独立后台壳、站点分析与聊天监管，公开站拆出主题切换与访问埋点

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

frontend/app/admin/messages/page.tsx

@@ -0,0 +1,22 @@
+import type { Metadata } from "next";
+import { cookies } from "next/headers";
+import { authCookieHeader } from "@/lib/cookies";
+import { getMeCached } from "@/lib/serverData";
+import { isStaff } from "@/lib/roles";
+import Forbidden from "../Forbidden";
+import MessagesAdmin from "./MessagesAdmin";
+
+export const metadata: Metadata = {
+  title: "消息管理",
+};
+
+/** 群聊（含大厅）与私聊分栏监管；鉴权与 staff API 一致 */
+export default async function AdminMessagesPage() {
+  const cookie = authCookieHeader(await cookies());
+  const me = await getMeCached(cookie || undefined);
+  if (!me.user || !isStaff(me.user.role)) {
+    return <Forbidden text="消息管理仅管理团队成员可进入。" />;
+  }
+
+  return <MessagesAdmin />;
+}