Mark prescription as dispensed — a governance-status flip only, for confirming an EXTERNAL fulfillment (same-day delivery / online pharmacy / print-retail) was handed off. Moves no stock. In-house prescriptions must use `dispense-inventory`, which runs the real dispense engine; this endpoint rejects them so a status-only call can't fake an in-house dispense (no decrement, no DEA entry, no estimate-line stamp).

Patient's last exam date (VCPR - Veterinary-Client-Patient Relationship)

Set when the dispense-from-inventory call included an InvoiceId and a line item was created atomically with the dispense. Lets clients append the line item locally without refetching.

The estimate the dispense was attached to — either the one the caller supplied or one auto-created/resolved server-side. Lets a client that had no estimate of its own adopt the server's estimate instead of failing to reconcile the line.

ISO date string (YYYY-MM-DD).