fix(go): batch durable kafka replay

go/vehicle-gateway/internal/eventbus/kafka_sink_test.go

@@ -64,6 +64,29 @@ func TestKafkaSinkRejectsUnknownProtocol(t *testing.T) {
 	}
 }
 
+func TestKafkaSinkPublishesDurableRecordsInSingleWriterCall(t *testing.T) {
+	writer := &recordingWriter{}
+	sink := newKafkaSinkWithWriter(writer, KafkaConfig{UnifiedTopic: "custom.unified"})
+	env := envelope.FrameEnvelope{Protocol: envelope.ProtocolJT808, Phone: "13307795425", MessageID: "0x0200"}
+
+	err := sink.PublishRecords(context.Background(), []durableRecord{
+		{Kind: "raw", Envelope: env},
+		{Kind: "unified", Envelope: env},
+	})
+	if err != nil {
+		t.Fatalf("PublishRecords() error = %v", err)
+	}
+	if writer.writeCalls != 1 {
+		t.Fatalf("WriteMessages calls = %d, want 1", writer.writeCalls)
+	}
+	if len(writer.messages) != 2 {
+		t.Fatalf("messages = %d, want 2", len(writer.messages))
+	}
+	if writer.messages[0].Topic != "vehicle.raw.jt808.v1" || writer.messages[1].Topic != "custom.unified" {
+		t.Fatalf("topics = %q, %q", writer.messages[0].Topic, writer.messages[1].Topic)
+	}
+}
+
 func TestNewKafkaSinkUsesProductionDeliveryGuarantees(t *testing.T) {
 	sink, err := NewKafkaSink(KafkaConfig{Brokers: []string{"127.0.0.1:9092"}})
 	if err != nil {
@@ -90,10 +113,12 @@ func TestNewKafkaSinkUsesProductionDeliveryGuarantees(t *testing.T) {
 }
 
 type recordingWriter struct {
-	messages []kafka.Message
+	messages   []kafka.Message
+	writeCalls int
 }
 
 func (w *recordingWriter) WriteMessages(_ context.Context, messages ...kafka.Message) error {
+	w.writeCalls++
 	w.messages = append(w.messages, messages...)
 	return nil
 }