Process refund.created events from the queue. Update the order row, send a confirmation email via @acme/http.

• conventionaddressedf_1
  Plan uses fetch directly; team standard is @acme/http
  Use @acme/http for outbound so traces and retries are picked up automatically.
• ownershipaddressedf_2
  Refund row writes are correctly scoped to the orders service
  No cross-service writes; only the orders row is mutated.