Extensiv: ASNs No Longer Fail On Items Without Lot Tracking

ASNs to Extensiv buildings were silently failing on items that don't have lot tracking turned on in Extensiv. Endless was attaching a lot number to every receiver line, and Extensiv was rejecting the whole receiver when the item wasn't lot-tracked, so the ASN never landed.

There's now a "Send lot number" setting on the Extensiv integration, off by default. Turn it on for accounts where every item is lot-tracked; leave it off otherwise and ASNs go through without a lot number attached. Integrations already configured to send a reference number as the lot number are unaffected — that setting still wins.