Widen admin layout to max-w-[1800px] to reduce empty side margins

admin-app/src/admin/AdminLayout.jsx

@@ -90,7 +90,7 @@ export default function AdminLayout() {
           <LogOut className="h-4 w-4" /> Выйти
         </button>
       </aside>
-      <main className="flex-1 p-5 sm:p-8 max-w-5xl">
+      <main className="flex-1 p-5 sm:p-8 max-w-[1800px]">
         <Outlet />
       </main>
     </div>