feat: 更新管理员导航，重定向菜单权限至根路径，添加角色同步API，移除菜单权限模块

src/components/admin/toolbar.tsx

@@ -93,8 +93,6 @@ export function ShellToolbar() {
     adminProfile?.username?.trim() ||
     "管理员";
 
-  const permissionCount = adminProfile?.permissions?.length ?? 0;
-
   function onLogout() {
     clearSession();
     toast.success("已退出登录");
@@ -170,15 +168,8 @@ export function ShellToolbar() {
               {initialsFromProfile(adminProfile)}
             </AvatarFallback>
           </Avatar>
-          <span className="hidden min-w-0 flex-1 flex-col sm:flex">
-            <span className="truncate text-sm font-semibold leading-tight">
-              {displayName}
-            </span>
-            <span className="truncate text-xs text-muted-foreground">
-              {permissionCount > 0
-                ? `${permissionCount} 项功能权限 · 菜单已按角色过滤`
-                : "重新登录可同步权限与侧栏菜单"}
-            </span>
+          <span className="hidden min-w-0 flex-1 truncate text-sm font-semibold leading-tight sm:block">
+            {displayName}
           </span>
           <ChevronDownIcon className="hidden size-4 shrink-0 text-muted-foreground sm:block" />
         </DropdownMenuTrigger>