完善角色与消息权限：收紧板管内容处置，彻底删除仅站长，并统一管理删帖/评弹窗。

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

frontend/app/admin/messages/page.tsx

@@ -2,7 +2,7 @@ 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 { canAccessAdminMessages } from "@/lib/roles";
 import Forbidden from "../Forbidden";
 import MessagesAdmin from "./MessagesAdmin";
 
@@ -10,13 +10,13 @@ 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 */
+/** 群聊（含大厅）与私聊分栏监管；鉴权与消息管理权限一致 */
 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。" />;
+  if (!me.user || !canAccessAdminMessages(me.user)) {
+    return <Forbidden text="消息管理需站长授予权限，或被任命为群管理员。" />;
   }
 
-  return <MessagesAdmin />;
+  return <MessagesAdmin me={me.user} />;
 }