- Run batch imports with bounded concurrency (IMPORT_BATCH_CONCURRENCY = 8) instead of fully sequentially, parallelizing network downloads and DB writes. - Collect FurnitureData.json entries and write the whole file once per batch (appendFurniEntriesBulk) instead of rewriting it on every single item. Catalog id allocation stays serialized and FurnitureData writes remain lock-guarded, so concurrent imports are safe.