feat: relocate import tools into studio and harden catalog/furnidata integrity

- Move /admin/import/* tools under /admin/studio/* and add studio nav, layout and tabs
- Add shared catalog maintenance panel plus a /admin/studio/maintenance tab
- Make furnidata reconciliation overwrite conflicting entries with the
  DB-authoritative items_base classname/id (surfaced via fixedConflicts)
- Add furnidata_translate_enabled setting to skip the heavy localized
  furnidata build during import (manual build-languages still forces it)
- Update staff smoke contract test for the studio hub

src/app/admin/studio/page.tsx

@@ -1,27 +1,5 @@
 import { redirect } from "next/navigation";
-import { StudioClient } from "@/components/admin/studio/studio-client";
-import { buildFurniImportSource } from "@/lib/habbo-gamedata-hotel";
-import { canAccess, getAdminContext, PERMS } from "@/lib/permissions";
-import { getTreeFlat } from "@/lib/services/catalog-tree";
-import { getHabboGamedataHotel } from "@/lib/services/habbo-gamedata-hotel";
 
-export default async function StudioPage(_props: {
-	params: Promise<{ locale: string }>;
-}) {
-	const { session, permissions } = await getAdminContext();
-	if (!canAccess(permissions, PERMS.ASSETS_IMPORT, session.user.rank)) {
-		redirect("/admin");
-	}
-
-	const [hotel, catalogTree] = await Promise.all([
-		getHabboGamedataHotel(),
-		getTreeFlat(),
-	]);
-
-	return (
-		<StudioClient
-			source={buildFurniImportSource(hotel)}
-			initialTree={catalogTree}
-		/>
-	);
+export default function StudioIndexPage() {
+	redirect("/admin/studio/furni");
 }