Ship part of an order or mark it ready for pickup

Fulfilment records how many units actually left, not just that the order is "shipped". That is what makes a partial shipment and the next one add up.

1. Open Orders and find a paid order.
2. Use the shipment action. The dialog lists each line with Remaining of Purchased already filled in.
3. Lower a quantity when only some units are going out. Submit, then repeat when the rest leave.
4. For shipping, enter the carrier and tracking number. The tracking URL is optional and must be https.
5. For pickup, mark the order ready when it is waiting, and hand it over when the customer collects it.

A shipment never changes your stock. The units were already committed when the order was paid; shipping is a record of them leaving, and only a return receipt puts resellable goods back.

The tracking number and link appear in the customer email and in the order page the customer opens. A tracking row migrated from before quantity tracking is marked for operator review: it shows the old tracking, but new fulfillment waits until someone resolves it.