feat(frontend): persist selected tab on admin settings page

frontend/app/(main)/admin/settings/page.tsx

@@ -1,8 +1,20 @@
 // Copyright 2026 Arctel.net
 // SPDX-License-Identifier: Apache-2.0
 
+import {Suspense} from "react"
+import {Loader2} from "lucide-react"
 import {AdminSettingsPageClient} from "./page-client"
 
 export default function AdminSettingsPage() {
-  return <AdminSettingsPageClient />
-}
+  return (
+    <Suspense
+      fallback={
+        <div className="flex items-center justify-center min-h-[400px]">
+          <Loader2 className="size-6 animate-spin text-primary" />
+        </div>
+      }
+    >
+      <AdminSettingsPageClient />
+    </Suspense>
+  )
+}