refactor: move admin entry into account menu

frontend/src/App.tsx

@@ -844,10 +844,14 @@ function AdminDashboard() {
 
 function AccountMenu({
   user,
+  adminActive,
+  onOpenAdmin,
   onUserUpdate,
   onLogout,
 }: {
   user: User;
+  adminActive: boolean;
+  onOpenAdmin: () => void;
   onUserUpdate: (user: User) => void;
   onLogout: () => void;
 }) {
@@ -867,9 +871,10 @@ function AccountMenu({
   return (
     <div className="account">
       <button
-        className="logout"
+        className={`logout ${adminActive ? "admin-active" : ""}`}
         onClick={() => setOpen((value) => !value)}
         aria-label="账户"
+        aria-expanded={open}
       >
         {user.label.slice(0, 1)}
       </button>
@@ -879,6 +884,21 @@ function AccountMenu({
             <strong>{user.label}</strong>
             <span>{user.role === "admin" ? "管理员" : "独立空间"}</span>
           </header>
+          {user.role === "admin" && (
+            <button
+              className={`account-admin ${adminActive ? "active" : ""}`}
+              onClick={() => {
+                onOpenAdmin();
+                setOpen(false);
+              }}
+            >
+              <span>
+                <strong>运行后台</strong>
+                <small>Agent 与系统活动</small>
+              </span>
+              <i aria-hidden="true">{adminActive ? "当前" : "›"}</i>
+            </button>
+          )}
           {user.role !== "admin" && (
             <label>
               <span>
@@ -958,17 +978,11 @@ function Notebook({
             想法
             {pending > 0 && <i aria-hidden="true" />}
           </button>
-          {user.role === "admin" && (
-            <button
-              className={view === "admin" ? "active" : ""}
-              onClick={() => switchView("admin")}
-            >
-              后台
-            </button>
-          )}
         </nav>
         <AccountMenu
           user={user}
+          adminActive={view === "admin"}
+          onOpenAdmin={() => switchView("admin")}
           onUserUpdate={onUserUpdate}
           onLogout={onLogout}
         />

frontend/src/styles.css

@@ -252,6 +252,11 @@ summary:focus-visible {
   letter-spacing: 0;
 }
 
+.logout.admin-active {
+  border-color: rgba(153, 104, 72, 0.34);
+  background: rgba(153, 104, 72, 0.06);
+}
+
 .account {
   position: relative;
   justify-self: end;
@@ -288,6 +293,52 @@ summary:focus-visible {
   font-size: 10px;
 }
 
+.account-admin {
+  width: 100%;
+  padding: 15px 18px;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 18px;
+  border: 0;
+  border-bottom: 1px solid var(--line);
+  background: transparent;
+  color: var(--ink);
+  text-align: left;
+  cursor: pointer;
+}
+
+.account-admin:hover,
+.account-admin.active {
+  background: rgba(153, 104, 72, 0.055);
+}
+
+.account-admin > span {
+  display: grid;
+  gap: 3px;
+}
+
+.account-admin strong {
+  font-size: 12px;
+  font-weight: 500;
+}
+
+.account-admin small {
+  color: var(--muted);
+  font-size: 10px;
+}
+
+.account-admin > i {
+  color: var(--warm);
+  font-size: 15px;
+  font-style: normal;
+}
+
+.account-admin.active > i {
+  font-size: 9px;
+  letter-spacing: 0.08em;
+}
+
 .account-menu > label {
   display: flex;
   align-items: center;