style: clean up the invoice and setup event for warehouse.

apps/edr-freight-api/src/modules/billing/billing.service.ts

@@ -96,11 +96,6 @@ export interface GenerateInvoiceInput {
    * (default PENDING) stamps `issuedAt`.
    */
   status?: Freight.InvoiceStatus;
-  /**
-   * Document number prefix for this source (e.g. `WHF` for warehouse fees);
-   * defaults to `FRT`. The daily sequence is allocated per prefix.
-   */
-  numberCode?: string;
 }
 
 /** Payload broadcast on `${source}.invoice.<event>`. */
@@ -665,11 +660,12 @@ export class BillingService {
     const result = await this.payment.initiate({
       referenceId: sourceId,
       source: invoice.source,
-      // Gateway reference type derives from the invoice source by convention
-      // (source.toUpperCase() ∈ PaymentReferenceType) — no domain word here, and
-      // the domain never supplies it. New sources add their uppercased value to
-      // the PaymentReferenceType enum.
-      referenceType: invoice.source.toUpperCase() as PaymentReferenceType,
+      // Freight payments settle under the generic SHIPMENT reference — how the
+      // payment service attributes them to the freight API. The payment ↔ invoice
+      // link is the intent id (`paymentId`); per-source post-payment reactions live
+      // in the domain via `${source}.invoice.paid`. Neither billing nor the payment
+      // service branches on a domain-specific reference type.
+      referenceType: PaymentReferenceType.SHIPMENT,
       orderRef: invoice.invoiceNumber,
       amountMinor: Math.round(Number(invoice.totalAmount)),
       currency: invoice.currency,