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/layout.tsx

@@ -2,10 +2,10 @@ import type { Metadata } from "next";
 import Link from "next/link";
 import { cookies } from "next/headers";
 import { ShieldAlert } from "lucide-react";
-import { authCookieHeader } from "@/lib/cookies";
-import { getMeCached } from "@/lib/serverData";
+import { authCookieHeader, TOKEN_COOKIE } from "@/lib/cookies";
+import { getMeCached, getPublicSettingsCached } from "@/lib/serverData";
 import { isStaff } from "@/lib/roles";
-import { AdminSidebar, AdminNavMobile } from "./AdminNav";
+import AdminShell from "@/components/admin/AdminShell";
 
 // 整个 /admin 树不进入索引（子页面无需重复声明）
 export const metadata: Metadata = {
@@ -15,42 +15,51 @@ export const metadata: Metadata = {
 // 权限以 Go 端 RequireStaff 为唯一判定；这里仅决定管理界面是否直出，
 // 非管理团队访问任意 /admin/* 时 SSR 统一给出无权限提示（所有写接口仍由后端 403 兜底）。
 export default async function AdminLayout({ children }: { children: React.ReactNode }) {
-  const cookie = authCookieHeader(await cookies());
+  const cookieStore = await cookies();
+  const cookie = authCookieHeader(cookieStore);
   const me = await getMeCached(cookie || undefined);
+  const settings = await getPublicSettingsCached();
+  const theme = cookieStore.get("j13-theme")?.value === "dark" ? "dark" : "light";
 
   if (!me.user || !isStaff(me.user.role)) {
     return (
-      <div className="max-w-md mx-auto panel p-8 text-center mt-6 lg:mt-10">
-        <span
-          className="inline-flex w-14 h-14 rounded-full items-center justify-center mb-4"
-          style={{ background: "var(--gold-soft)", color: "var(--gold)" }}
-        >
-          <ShieldAlert size={26} />
-        </span>
-        <h1 className="text-lg font-extrabold" style={{ color: "var(--ink)" }}>
-          需要管理员权限
-        </h1>
-        <p className="meta mt-2 text-[13px]">此区域仅供站点管理员访问，如有疑问请联系站长。</p>
-        <Link href="/" className="btn btn-primary mt-6">
-          返回首页
-        </Link>
+      <div
+        data-admin-viewport
+        id="main"
+        tabIndex={-1}
+        className="min-h-screen flex items-center justify-center px-4 outline-none"
+        style={{ background: "var(--bg)" }}
+      >
+        <div className="max-w-md w-full panel p-8 text-center">
+          <span
+            className="inline-flex w-14 h-14 rounded-full items-center justify-center mb-4"
+            style={{ background: "var(--gold-soft)", color: "var(--gold)" }}
+          >
+            <ShieldAlert size={26} />
+          </span>
+          <h1 className="text-lg font-extrabold" style={{ color: "var(--ink)" }}>
+            需要管理员权限
+          </h1>
+          <p className="meta mt-2 text-[13px]">此区域仅供站点管理员访问，如有疑问请联系站长。</p>
+          <Link href="/" className="btn btn-primary mt-6">
+            返回首页
+          </Link>
+        </div>
       </div>
     );
   }
 
+  // 未读仅在有 access cookie 时才可信；壳层铃铛用 SSR 直出避免挂载后才出红点
+  const unread = cookieStore.get(TOKEN_COOKIE)?.value ? me.unread_count : 0;
+
   return (
-    <div>
-      <AdminNavMobile user={me.user} />
-      <div className="flex items-start gap-6 xl:gap-7">
-        {/* sticky 必须钉在 aside 自身：内层与侧栏同高时等于没钉住，会跟着主栏一起滚 */}
-        <aside
-          className="hidden lg:block w-60 xl:w-64 shrink-0 sticky self-start z-20 max-h-[calc(100vh-6.5rem)] overflow-y-auto"
-          style={{ top: 84 }}
-        >
-          <AdminSidebar user={me.user} />
-        </aside>
-        <section className="flex-1 min-w-0">{children}</section>
-      </div>
-    </div>
+    <AdminShell
+      user={me.user}
+      siteName={settings.site_name || "姜十三论坛"}
+      initialTheme={theme}
+      initialUnread={unread}
+    >
+      {children}
+    </AdminShell>
   );
 }