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.ts

@@ -485,7 +485,12 @@ export interface FurniDataReconcileResult {
 	normalizedIds: number;
 	/** items_base rows with no matching furnitype entry (need re-import). */
 	missing: number;
-	/** spriteIds used by a different classname in the file; left untouched. */
+	/** spriteIds used by a different classname in the file, now resolved by
+	 *  overwriting the entry's classname with the items_base (authoritative)
+	 *  value so the client renders the correct furniture. */
+	fixedConflicts: number;
+	/** spriteIds still used by a different classname after the pass (none, once
+	 *  fixedConflicts resolves every conflict). */
 	conflicts: number;
 }
 
@@ -498,8 +503,10 @@ export interface FurniDataReconcileResult {
  *   the emulator's catalog offer lookup stays in sync with the local ids;
  * - rows missing entirely from the file are counted (they need a re-import
  *   or batch-regen, since building an entry requires the SWF/nitro metadata);
- * - genuine spriteId conflicts (id used by a different classname) are counted
- *   but never auto-fixed.
+ * - genuine spriteId conflicts (id used by a different classname) are resolved
+ *   in favour of items_base: the furnidata entry occupying that id has its
+ *   classname overwritten with the items_base classname, so the client renders
+ *   the real (imported) furniture instead of a legacy/conflicting one.
  */
 export async function reconcileFurniDataWithItemsBase(): Promise<FurniDataReconcileResult> {
 	return withFurniDataLock(async () => {
@@ -539,7 +546,8 @@ export async function reconcileFurniDataWithItemsBase(): Promise<FurniDataReconc
 		let fixedOfferIds = 0;
 		let normalizedIds = 0;
 		let missing = 0;
-		let conflicts = 0;
+		let fixedConflicts = 0;
+		const conflicts = 0;
 
 		const entryOfferId = (entry: Record<string, unknown>): number => {
 			const v = Number(entry.offerid);
@@ -551,7 +559,17 @@ export async function reconcileFurniDataWithItemsBase(): Promise<FurniDataReconc
 			const existing = byId.get(spriteId);
 			if (existing) {
 				if (existing.entry.classname !== row.itemName) {
-					conflicts++;
+					// items_base is authoritative: this furnidata entry sits at the
+					// wrong classname for this id (legacy/conflicting data). Overwrite
+					// it so the client renders the imported furniture, not a stray one.
+					const displaced = String(existing.entry.classname ?? "");
+					existing.entry.classname = row.itemName;
+					existing.entry.id = spriteId;
+					existing.entry.offerid = spriteId;
+					// Keep the in-memory maps coherent for the corrected classname.
+					byClass.set(row.itemName, existing);
+					if (displaced) byClass.delete(displaced);
+					fixedConflicts++;
 				} else if (entryOfferId(existing.entry) !== spriteId) {
 					existing.entry.offerid = spriteId;
 					fixedOfferIds++;
@@ -589,10 +607,17 @@ export async function reconcileFurniDataWithItemsBase(): Promise<FurniDataReconc
 			}
 		}
 
-		if (fixedIds > 0 || fixedOfferIds > 0) {
+		if (fixedIds > 0 || fixedOfferIds > 0 || fixedConflicts > 0) {
 			await writeFurniData(furniData as Record<string, unknown>);
 		}
-		return { fixedIds, fixedOfferIds, normalizedIds, missing, conflicts };
+		return {
+			fixedIds,
+			fixedOfferIds,
+			normalizedIds,
+			missing,
+			fixedConflicts,
+			conflicts,
+		};
 	});
 }