Archiving An Order Fulfillment Now Clears Its Items Too

Archiving an order fulfillment used to leave its underlying fulfillment items live behind it. Cancels, unfulfills, and a few Shopify paths all hit this — the fulfillment looked archived, but its items kept hanging around and could show up in downstream lookups. Archiving now cascades to the items in one step, so an archived fulfillment really is fully archived. A separate backfill is queued for the historical rows that were affected.