refactor: rename admin route group to manage

app/(manage)/manage/benchmarks/page.tsx

@@ -0,0 +1,10 @@
+import type { Metadata } from "next"
+import { BenchmarksClient } from "./benchmarks-client"
+
+export const metadata: Metadata = {
+  title: "Benchmarks",
+}
+
+export default function BenchmarksPage() {
+  return <BenchmarksClient />
+}