feat(catalog): store furniture bundles as .hab instead of .nitro

Every bundle the CMS writes — upload, clone, sync, repair and the pet /
effect / figure importers — now lands as `<classname>.hab`, the extension
this deployment's renderer asks for. `.hab` and `.nitro` are the same
container, so an upload of either extension is accepted.

Resolution goes through one module, src/lib/furni/bundle-file.ts, so
nothing has to know the extension twice. Every existence check probes
`.hab` first and falls back to `.nitro`: the on-disk asset set is still
predominantly `.nitro`, and without the fallback Studio would report every
imported item as missing and the cleanup scan would classify 18k live
bundles as fake leftovers. Downloads are unchanged — Habbo's CDN and every
configured clone source still serve `.nitro`, so the conversion happens on
write, not on request.

Deliberately unchanged: the staged-attachment store in furni-attachment.ts
keys on a UUID and never reaches the client, so renaming it would break
in-flight recovery jobs.

Adds scripts/migrate-nitro-to-hab.ts to rename the existing asset set. It
refuses to run without --dry-run or --yes, never overwrites an existing
.hab, never deletes, and is idempotent.

Note: renderer-config.json lives outside this repo and was patched to
.hab separately; that file is served with a 30-day max-age, so returning
clients need a cms-client cache purge to pick the change up.

src/lib/services/pet-import.ts

@@ -1,4 +1,9 @@
 import { existsSync, promises as fs } from "node:fs";
+import {
+	bundleExistsInDir,
+	bundleWritePathInDir,
+	existingBundlePaths,
+} from "@/lib/furni/bundle-file";
 import { downloadFile } from "@/lib/services/import/core/download";
 import { CANONICAL_PETS, resolvePetSwfUrl } from "@/lib/services/pet-source";
 import { convertSwfToNitro } from "@/lib/services/swf-to-nitro";
@@ -35,11 +40,14 @@ export async function ensurePetDirs(): Promise<void> {
 	);
 }
 
+// Imports write `.hab`, the extension the client requests. A pet whose bundle
+// predates that (`.nitro`) still counts as imported until it is re-imported.
 function nitroPathFor(lib: string): string {
-	return getRuntimePath(
-		/*turbopackIgnore: true*/ PET_NITRO_DIR,
-		`${lib}.nitro`,
-	);
+	return bundleWritePathInDir(/*turbopackIgnore: true*/ PET_NITRO_DIR, lib);
+}
+
+function petBundleExists(lib: string): boolean {
+	return bundleExistsInDir(/*turbopackIgnore: true*/ PET_NITRO_DIR, lib);
 }
 
 export async function importSinglePet(params: {
@@ -99,19 +107,23 @@ export async function importSinglePet(params: {
 export async function deleteImportedPet(
 	lib: string,
 ): Promise<{ deletedFile: boolean }> {
-	const p = nitroPathFor(lib);
-	if (existsSync(/*turbopackIgnore: true*/ p)) {
+	// Remove both conventions so a re-import cannot resurrect a stale bundle.
+	const paths = existingBundlePaths(
+		[/*turbopackIgnore: true*/ PET_NITRO_DIR],
+		lib,
+	);
+	if (paths.length === 0) return { deletedFile: false };
+	for (const p of paths) {
 		await fs.unlink(/*turbopackIgnore: true*/ p).catch(() => {});
-		return { deletedFile: true };
 	}
-	return { deletedFile: false };
+	return { deletedFile: true };
 }
 
 export function getPetList(search: string): PetListItem[] {
 	const term = search.trim().toLowerCase();
 	const list = CANONICAL_PETS.map((lib) => ({
 		lib,
-		nitroExists: existsSync(/*turbopackIgnore: true*/ nitroPathFor(lib)),
+		nitroExists: petBundleExists(lib),
 	}));
 	return term ? list.filter((p) => p.lib.toLowerCase().includes(term)) : list;
 }
@@ -121,9 +133,7 @@ export function getPetStats(): {
 	imported: number;
 	missing: number;
 } {
-	const imported = CANONICAL_PETS.filter((lib) =>
-		existsSync(/*turbopackIgnore: true*/ nitroPathFor(lib)),
-	).length;
+	const imported = CANONICAL_PETS.filter((lib) => petBundleExists(lib)).length;
 	return {
 		total: CANONICAL_PETS.length,
 		imported,