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/lib/services/furni-data-i18n.ts

@@ -41,6 +41,22 @@ export const FURNIDATA_LANGUAGES = [
 
 export type FurnidataLang = (typeof FURNIDATA_LANGUAGES)[number]["lang"];
 
+/**
+ * Master switch for FurnitureData localization. Rebuilding the per-language
+ * files deep-clones the 100k+ entry master 13× and hits LibreTranslate, which
+ * can spike RAM/CPU on every import. Admins can disable it in settings to skip
+ * the work entirely (the master FurnitureData.json is still written by the
+ * import itself). The manual "build languages" action passes `force` to run
+ * regardless.
+ */
+async function translationEnabled(): Promise<boolean> {
+	try {
+		return await siteSettings.getBool("furnidata_translate_enabled", true);
+	} catch {
+		return true;
+	}
+}
+
 export interface LanguageFileResult {
 	lang: string;
 	hotel: string;
@@ -415,9 +431,15 @@ function cloneFurniData(
  * translation exists for that classname. Runs under the furnidata lock so it
  * never interleaves with concurrent imports.
  */
-export async function buildLocalizedFurniDataFiles(): Promise<
-	LanguageFileResult[]
-> {
+export async function buildLocalizedFurniDataFiles(
+	force = false,
+): Promise<LanguageFileResult[]> {
+	if (!force && !(await translationEnabled())) {
+		logger.debug(
+			"[furni-i18n] FurnitureData translation disabled by setting; skipping localized build.",
+		);
+		return [];
+	}
 	return withFurniDataLock(async () => {
 		const master = (await readFurniData()) as Record<
 			string,
@@ -554,8 +576,15 @@ export async function buildLocalizedFurniDataFiles(): Promise<
  */
 export async function patchLocalizedFurniDataEntries(
 	entries: Array<{ classname: string; name?: string; description?: string }>,
+	force = false,
 ): Promise<LanguageFileResult[]> {
 	if (entries.length === 0) return [];
+	if (!force && !(await translationEnabled())) {
+		logger.debug(
+			"[furni-i18n] FurnitureData translation disabled by setting; skipping localized patch.",
+		);
+		return [];
+	}
 
 	return withFurniDataLock(async () => {
 		const maps = await Promise.all(