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/api/admin/studio/nitro-cleanup/auto-clean/route.ts

@@ -0,0 +1,54 @@
+import { apiError, apiOk } from "@/lib/api";
+import { withAdmin } from "@/lib/api-handler";
+import { PERMS } from "@/lib/permissions";
+import { logAudit } from "@/lib/services/audit";
+import { clearFurniImportCache } from "@/lib/services/furni-import-cache";
+import { autoCleanFakeNitros } from "@/lib/services/nitro-cleanup";
+
+/** Automatically remove fake .nitro leftovers older than `maxAgeDays`. */
+export const POST = withAdmin(
+	{ permission: PERMS.ASSETS_IMPORT },
+	async (request, ctx) => {
+		let body: { maxAgeDays?: unknown };
+		try {
+			body = await request.json();
+		} catch {
+			return apiError("Invalid JSON body", 400);
+		}
+		const maxAgeDays =
+			typeof body?.maxAgeDays === "number" && Number.isFinite(body.maxAgeDays)
+				? Math.max(0, Math.floor(body.maxAgeDays))
+				: 30;
+		try {
+			const result = await autoCleanFakeNitros(maxAgeDays);
+			clearFurniImportCache();
+			if (result.deleted > 0) {
+				logAudit({
+					userId: ctx.session.user.id,
+					action: "nitro_auto_cleanup",
+					target: "NitroFiles",
+					after: {
+						maxAgeDays,
+						deleted: result.deleted,
+						copiesRemoved: result.copiesRemoved,
+						skippedRecent: result.skippedRecent,
+						skippedBroken: result.skippedBroken,
+						errors: result.errors.length > 0 ? result.errors : undefined,
+					},
+				});
+			}
+			return apiOk({
+				deleted: result.deleted,
+				copiesRemoved: result.copiesRemoved,
+				skippedRecent: result.skippedRecent,
+				skippedBroken: result.skippedBroken,
+				errors: result.errors.length > 0 ? result.errors : undefined,
+			});
+		} catch (err) {
+			return apiError(
+				`Nitro auto-cleanup failed: ${(err as Error).message}`,
+				500,
+			);
+		}
+	},
+);