fix: harden upstream and downstream receipt delivery

api/src/send-chain/gateway-events.controller.spec.ts

@@ -4,7 +4,9 @@ import { GatewayEventsController } from './gateway-events.controller';
 describe('GatewayEventsController protocol logging', () => {
   const sendChain = {
     handleSubmitResult: jest.fn(),
+    handleSubmitSegmentResult: jest.fn(),
     handleReceipt: jest.fn(),
+    intakeReceipt: jest.fn(),
   };
   const protocolLogs = {
     record: jest.fn(),
@@ -30,6 +32,51 @@ describe('GatewayEventsController protocol logging', () => {
     expect(protocolLogs.record).not.toHaveBeenCalled();
   });
 
+  it('persists each supplier segment response without adding a duplicate protocol log', async () => {
+    sendChain.handleSubmitSegmentResult.mockResolvedValue({ accepted: true });
+    const body = {
+      messageId: 'MSG-LONG-1',
+      channelId: 'channel-1',
+      submitId: 'submit-1',
+      segmentIndex: 2,
+      segmentTotal: 3,
+      gatewayMessageId: '456',
+      sequenceId: 8,
+      submitStatus: 'accepted' as const,
+    };
+
+    await expect(controller.submitSegmentResult(body)).resolves.toEqual({ accepted: true });
+    expect(sendChain.handleSubmitSegmentResult).toHaveBeenCalledWith(body);
+    expect(protocolLogs.record).not.toHaveBeenCalled();
+  });
+
+  it('logs a supplier receipt only after it is durably accepted by the inbox', async () => {
+    sendChain.intakeReceipt.mockResolvedValue({ accepted: true, inboxId: 'inbox-1', status: 'pending' });
+    const body = {
+      messageId: 'receipt-456',
+      channelId: 'channel-1',
+      connectionId: 'channel-1:0',
+      gatewayMessageId: '456',
+      phoneNumber: '13127620092',
+      receiptStatus: 'undelivered' as const,
+      rawStatus: 'UNDELIV',
+    };
+
+    await expect(controller.receiptIntake(body)).resolves.toEqual({
+      accepted: true,
+      inboxId: 'inbox-1',
+      status: 'pending',
+    });
+    expect(protocolLogs.record).toHaveBeenCalledWith(expect.objectContaining({
+      direction: 'channel_to_platform',
+      eventType: 'deliver_receipt',
+      channelId: 'channel-1',
+      messageId: 'receipt-456',
+      gatewayMessageId: '456',
+      status: 'success',
+    }));
+  });
+
   it('accepts only safe outbound Gateway packet events', () => {
     expect(controller.protocolLog({
       protocol: 'cmpp',