fix: normalize yutong mqtt mileage units

go/vehicle-gateway/internal/protocol/yutongmqtt/parser_test.go

@@ -64,6 +64,22 @@ func TestParseMessageUsesDeviceAsVehicleKeyWhenNotVIN(t *testing.T) {
 	assertFloatField(t, env, envelope.FieldSpeedKMH, 12.3)
 }
 
+func TestParseMessageNormalizesProductionMileageMeters(t *testing.T) {
+	payload := []byte(`{
+	  "device":"LMRKH9AC3R1004101",
+	  "time":"2026-07-02 01:02:04.085",
+	  "data":{"TOTAL_MILEAGE":56905000,"METER_SPEED":19}
+	}`)
+	env, err := ParseMessage("yutong", "/ytforward/shln/1", payload, 1782940000000)
+	if err != nil {
+		t.Fatalf("ParseMessage() error = %v", err)
+	}
+	assertFloatField(t, env, envelope.FieldTotalMileageKM, 56905)
+	if env.EventTimeMS != 1782925324085 {
+		t.Fatalf("event time = %d, want 1782925324085", env.EventTimeMS)
+	}
+}
+
 func TestParseMessageRejectsMalformedJSON(t *testing.T) {
 	_, err := ParseMessage("endpoint-a", "/bad", []byte("{bad-json"), 1782745114999)
 	if !errors.Is(err, ErrInvalidJSON) {