Remap occupied furniture IDs during Catalog Studio imports

src/lib/services/furni-import.ts

@@ -37,6 +37,7 @@ import {
 } from "@/lib/services/swf-to-nitro";
 import { getRuntimePath } from "@/lib/utils/runtime-path";
 import type { ImportSingleResult } from "@/types/furni";
+import { reserveFurnitureId } from "./furniture-id-reservation";
 
 // Re-export the download helpers now owned by the shared import core.
 // Existing furni callers keep importing them from here.
@@ -563,8 +564,8 @@ export async function importSingleFurni(params: {
 			error: `Item "${classname}" already exists with id ${existsByName.id} — cannot reassign to spriteId ${originalId}`,
 		};
 	}
-	const itemId = repairExisting && existsByName ? existsByName.id : originalId;
-	const spriteId =
+	let itemId = repairExisting && existsByName ? existsByName.id : originalId;
+	let spriteId =
 		repairExisting && existsByName ? existsByName.spriteId : originalId;
 	const preservingExisting = !!(repairExisting && existsByName);
 	const [existsById] = await db
@@ -572,7 +573,7 @@ export async function importSingleFurni(params: {
 		.from(ItemsBase)
 		.where(eq(ItemsBase.id, itemId))
 		.limit(1);
-	if (existsById && (!existsByName || existsById.itemName !== classname)) {
+	if (existsByName && existsById && existsById.itemName !== classname) {
 		// The spriteId is owned by a different classname. Even with
 		// updateExisting this is a genuine conflict, not an update.
 		return {
@@ -586,7 +587,7 @@ export async function importSingleFurni(params: {
 
 	// ── Check if spriteId already used in FurnitureData.json ──
 	const takenBy = await findFurniDataIdConflict(spriteId, classname);
-	if (takenBy) {
+	if (takenBy && isUpdate) {
 		return {
 			ok: false,
 			warnings,
@@ -634,10 +635,20 @@ export async function importSingleFurni(params: {
         WHERE id = ${spriteId}
       `);
 		} else {
-			await db.execute(sql`
-        INSERT INTO items_base (id, sprite_id, public_name, item_name, type)
-        VALUES (${spriteId}, ${spriteId}, ${bestName}, ${classname}, ${itemType})
-      `);
+			itemId = await reserveFurnitureId(
+				originalId,
+				classname,
+				async (allocatedId) => {
+					await db.execute(
+						sql`INSERT INTO items_base (id, sprite_id, public_name, item_name, type) VALUES (${allocatedId}, ${allocatedId}, ${bestName}, ${classname}, ${itemType})`,
+					);
+				},
+			);
+			spriteId = itemId;
+			if (spriteId !== originalId)
+				warnings.push(
+					`Source ID ${originalId} is occupied; imported with local ID ${spriteId}`,
+				);
 		}
 	} catch (err) {
 		return {