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/features/housekeeping/foundation/foundation-source-contract.test.ts

@@ -561,7 +561,7 @@ describe("housekeeping foundation completion contracts", () => {
 		}
 	});
 
-	it("creates the real six-domain registry in locked order without workflows", () => {
+	it("creates the real six-domain registry in locked order without approved workflows", () => {
 		const registry = createHousekeepingRegistry(HOUSEKEEPING_MANIFESTS);
 
 		expect(registry.domains.map((domain) => domain.id)).toEqual([
@@ -572,9 +572,20 @@ describe("housekeeping foundation completion contracts", () => {
 			"hotel",
 			"system",
 		]);
-		expect(registry.domains.every((domain) => domain.routes.length === 0)).toBe(
-			true,
-		);
+		expect(
+			registry.domains
+				.filter((domain) => domain.id !== "hotel")
+				.every((domain) => domain.routes.length === 0),
+		).toBe(true);
+		expect(
+			registry.domains.find((domain) => domain.id === "hotel")?.routes,
+		).toEqual([
+			expect.objectContaining({
+				id: "nitro-cleanup",
+				href: "/admin-next/hotel/nitro-cleanup",
+				labelKey: "pages.housekeeping.domains.hotel.routes.nitroCleanup",
+			}),
+		]);
 	});
 
 	it("keeps production preview disabled even when the flag is true", () => {