feat(studio): expand nitro cleanup with repair, auto-clean, and orphaned assets

Scan distinguishes fake, broken, and orphaned SWF/icon assets with age
metadata, deletes per asset kind, re-downloads broken nitro bundles from
configured sources, auto-cleans old fake leftovers, and exports a JSON
manifest. Adds rebuild and auto-clean API endpoints with audit coverage
and a housekeeping preview route under the hotel domain.

Verified: full vitest suite (2213 tests), typecheck, and biome all pass.

src/app/admin-next/hotel/nitro-cleanup/page.tsx

@@ -0,0 +1,5 @@
+import { NitroCleanupPanel } from "@/components/admin/studio/nitro-cleanup-panel";
+
+export default function HousekeepingHotelNitroCleanupPage() {
+	return <NitroCleanupPanel />;
+}