Refund status tracked separately from order status

When refund state is encoded only as order.status = 'refunded', the system cannot represent intermediate states: a refund that was requested but not yet processed, a refund that the payment provider rejected, or an order that was cancelled without a refund being issued at all (e.g., store credit was given instead). This is an iso-25010:2011 functional correctness failure and a GDPR Art. 17 (right to erasure / financial correction) accountability gap. Separate refund tracking also enables storing the provider's refund ID — essential for reconciling Stripe refunds against your own records and for debugging partial or failed refunds.

Create a separate Refund model in prisma/schema.prisma with its own independent status lifecycle, and initiate refunds through a dedicated function in lib/refunds/create.ts.

// prisma/schema.prisma:
// model Refund {
//   id               String   @id @default(cuid())
//   orderId          String
//   amount           Int      // cents
//   status           String   // pending | processing | completed | failed
//   providerRefundId String?
//   reason           String?
//   initiatedBy      String?
//   createdAt        DateTime @default(now())
//   updatedAt        DateTime @updatedAt
//   order            Order    @relation(fields: [orderId], references: [id])
// }

export async function initiateRefund(orderId: string, amount: number, reason: string, actorId: string) {
  return db.refund.create({
    data: { orderId, amount, status: 'pending', reason, initiatedBy: actorId },
  })
}