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/app/admin/import/furni/upload/upload-furni-client.tsx

@@ -282,17 +282,19 @@ export function UploadFurniClient() {
 						<div className="text-sm font-medium">Files</div>
 
 						<div className="space-y-1.5">
-							<Label htmlFor="nitro">.nitro file *</Label>
+							<Label htmlFor="nitro">.hab file *</Label>
 							<Input
 								ref={nitroRef}
 								id="nitro"
 								type="file"
-								accept=".nitro"
+								accept=".hab,.nitro"
 								onChange={(e) => setNitroFile(e.target.files?.[0] ?? null)}
 								required
 							/>
 							<p className="text-xs text-muted-foreground">
-								The .nitro bundle file (max 50MB)
+								The furniture bundle (max 50MB). Stored as{" "}
+								<code className="font-mono">.hab</code>; a{" "}
+								<code className="font-mono">.nitro</code> is accepted too.
 							</p>
 						</div>
 

src/app/admin/studio/upload/page.tsx

@@ -13,10 +13,10 @@ export default async function StudioUploadPage(_props: {
 		<div className="space-y-6 p-4">
 			<div>
 				<h1 className="text-2xl font-bold tracking-tight">
-					Upload .nitro Furniture
+					Upload .hab Furniture
 				</h1>
 				<p className="mt-1 text-muted-foreground">
-					Upload a .nitro bundle and optional icon to import furniture into the
+					Upload a .hab bundle and optional icon to import furniture into the
 					hotel. The database entry, catalog item, and FurnitureData.json will
 					be updated automatically.
 				</p>