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/layout.tsx

@@ -1,14 +1,15 @@
 import type { Metadata } from "next";
-import { cookies } from "next/headers";
+import { cookies, headers } from "next/headers";
 import { Plus_Jakarta_Sans, Noto_Sans_SC, JetBrains_Mono } from "next/font/google";
 import "./globals.css";
-import Header from "@/components/Header";
-import Footer from "@/components/Footer";
+import SiteChrome from "@/components/SiteChrome";
 import Toaster from "@/components/Toaster";
 import TipHost from "@/components/TipHost";
 import AccountGuard from "@/components/AccountGuard";
 import ThemeSync from "@/components/ThemeSync";
 import RealtimeProvider from "@/components/RealtimeProvider";
+import VisitBeacon from "@/components/VisitBeacon";
+import PostLinkProvider from "@/components/PostLinkProvider";
 import CodeFoldProvider from "@/components/markdown/CodeFoldProvider";
 import MotionProvider from "@/components/MotionProvider";
 import CommentsPolicyProvider from "@/components/CommentsPolicyProvider";
@@ -65,6 +66,11 @@ export default async function RootLayout({
   children: React.ReactNode;
 }) {
   const cookieStore = await cookies();
+  const headerStore = await headers();
+  // middleware 写入 x-pathname；供 SiteChrome SSR 初值（软导航靠客户端 pathname）
+  const pathname = headerStore.get("x-pathname") || "";
+  const isAdmin = pathname === "/admin" || pathname.startsWith("/admin/");
+
   // 浅色优先的设计系统，仅在显式选择暗色时挂 .dark
   const theme = cookieStore.get("j13-theme")?.value === "dark" ? "dark" : "light";
 
@@ -113,35 +119,33 @@ export default async function RootLayout({
         <a href="#main" className="skip-link">
           跳到主要内容
         </a>
-        <Header
-          initialUser={user}
-          initialUnread={unread}
-          initialChatUnread={chatUnread}
-          initialTheme={theme}
-          siteName={settings.site_name}
-          allowRegister={settings.allow_register}
-        />
-        <main
-          id="main"
-          tabIndex={-1}
-          className="flex-1 w-full max-w-[1440px] mx-auto px-4 sm:px-6 py-7 sm:py-9 outline-none"
-        >
-          <MotionProvider initial={motionCfg}>
-            <CommentsPolicyProvider allowComments={settings.allow_comments !== false}>
+        <MotionProvider initial={motionCfg}>
+          <CommentsPolicyProvider allowComments={settings.allow_comments !== false}>
+            <PostLinkProvider openInNewTab={settings.post_link_new_tab !== false}>
               <CodeFoldProvider
                 initialEnabled={settings.code_block_auto_fold}
                 initialFoldLines={settings.code_block_fold_lines}
               >
-                {children}
+                <SiteChrome
+                  initialIsAdmin={isAdmin}
+                  user={user}
+                  unread={unread}
+                  chatUnread={chatUnread}
+                  theme={theme}
+                  siteName={settings.site_name}
+                  allowRegister={settings.allow_register}
+                >
+                  {children}
+                </SiteChrome>
               </CodeFoldProvider>
-            </CommentsPolicyProvider>
-          </MotionProvider>
-        </main>
-        <Footer siteName={settings.site_name} />
+            </PostLinkProvider>
+          </CommentsPolicyProvider>
+        </MotionProvider>
         <Toaster />
         <TipHost />
         <AccountGuard />
         <ThemeSync initialAccent={accent || ""} />
+        <VisitBeacon />
         <RealtimeProvider userId={user ? user.id : null} />
       </body>
     </html>