feat(club-003): club POS integration: identify member and register cashback from sales

project/src/modules/pos/domain/pos-sale.ts

@@ -59,6 +59,8 @@ export interface PosSaleInput {
   customerId?: string;
   /** Optional label for pending sales without customer */
   posLabel?: string;
+  /** Club member ID — if provided and sale completes, cashback is accumulated to the member's ledger. */
+  clubMemberId?: string;
 }
 
 export interface PosReceiptItem {
@@ -128,6 +130,10 @@ export interface PosSaleResult {
   payments: PosPaymentResult[];
   receipt: PosReceipt;
   createdAt: Date;
+  /** Cashback accumulated to the Club member's ledger (0 if no clubMemberId or sale is PENDING). */
+  clubEarnedCents: number;
+  /** Club member code when a clubMemberId was provided. */
+  clubMemberCode?: string;
 }
 
 export interface PosPaymentResult extends PosReceiptPayment {