feat: add ads/sponsor/captcha modules and polish home & chat UI

frontend/components/admin/AdminShell.tsx

@@ -1,4 +1,4 @@
-"use client";
+"use client";
 
 import Link from "next/link";
 import { usePathname, useRouter } from "next/navigation";
@@ -22,6 +22,7 @@ import {
   Settings,
   ChevronDown,
   FileText,
+  CircleDollarSign,
 } from "lucide-react";
 import type { User } from "@/lib/api";
 import { apiAdminPendingCounts, apiLogout } from "@/lib/api";
@@ -87,10 +88,16 @@ const NAV_GROUPS: NavGroup[] = [
       },
       {
         href: "/admin/pages",
-        label: "单页",
+        label: "单页管理",
         icon: FileText,
         visible: (u) => isAdminOrAbove(u.role),
       },
+      {
+        href: "/admin/ads",
+        label: "推广与赞助",
+        icon: CircleDollarSign,
+        visible: (u) => isAdminOrAbove(u.role),
+      },
     ],
   },
   {