fix: materialize stationary yutong daily mileage

go/vehicle-gateway/internal/stats/daily_metric_test.go

@@ -1838,6 +1838,107 @@ func TestWriterSkipsConsecutiveDuplicateMileageSamples(t *testing.T) {
 	}
 }
 
+func TestWriterCarriesPreviousYutongMileageIntoStationaryDay(t *testing.T) {
+	exec := &recordingExec{}
+	loc := time.FixedZone("Asia/Shanghai", 8*3600)
+	writer := NewWriter(exec, loc)
+	eventTime := time.Date(2026, 7, 19, 6, 5, 42, 0, loc)
+	previousTime := time.Date(2026, 7, 18, 16, 48, 10, 0, loc)
+	vin := "LMRKH9AC9R1004099"
+	sourceKey := "YUTONG_MQTT:" + vin + "@PLATFORM:yutong"
+	sample := MetricSample{
+		VIN:       vin,
+		Protocol:  envelope.ProtocolYutongMQTT,
+		StatDate:  "2026-07-19",
+		SourceKey: sourceKey,
+	}
+	writer.baselineCache[mileageCacheKey(sample)] = sourceBaselineCacheEntry{
+		baseline: sourceBaseline{
+			LatestTotalKM:   24245,
+			LatestEventTime: previousTime,
+			QualityReason:   QualityReasonHistorical,
+		},
+		found:    true,
+		cachedAt: time.Now(),
+	}
+	event := managedTestSource(envelope.FrameEnvelope{
+		Protocol:       envelope.ProtocolYutongMQTT,
+		VIN:            vin,
+		DeviceID:       vin,
+		SourceEndpoint: "mqtt://yutong/ytforward/shln/2",
+		SourceCode:     "yutong",
+		PlatformName:   "宇通",
+		EventTimeMS:    eventTime.UnixMilli(),
+		ReceivedAtMS:   eventTime.UnixMilli(),
+		Fields: map[string]any{
+			"yutong_mqtt.data.latitude":    "30.645438",
+			"yutong_mqtt.data.longitude":   "114.435672",
+			"yutong_mqtt.data.meter_speed": "0",
+		},
+	})
+
+	result, err := writer.AppendWithResult(context.Background(), event)
+	if err != nil {
+		t.Fatalf("AppendWithResult() error = %v", err)
+	}
+	if result.SamplesRecoveredStationary != 1 || result.SamplesWritten != 1 || result.ProjectionsWritten != 1 {
+		t.Fatalf("stationary carry result = %+v", result)
+	}
+	if result.SamplesSkippedMissingMileage != 1 {
+		t.Fatalf("source-data evidence must retain the missing-mileage counter: %+v", result)
+	}
+	if len(exec.calls) != 7 {
+		t.Fatalf("exec calls = %d, want source touch plus six mileage writes", len(exec.calls))
+	}
+	sourceWrite := exec.calls[1]
+	if !strings.Contains(sourceWrite.query, "INSERT INTO vehicle_daily_mileage_source") {
+		t.Fatalf("source mileage write missing: %s", sourceWrite.query)
+	}
+	if got := sourceWrite.args[9]; got != float64(24245) {
+		t.Fatalf("first total mileage = %#v, want carried 24245", got)
+	}
+	if got := sourceWrite.args[10]; got != float64(24245) {
+		t.Fatalf("latest total mileage = %#v, want carried 24245", got)
+	}
+	if got := sourceWrite.args[11]; got != float64(0) {
+		t.Fatalf("daily mileage = %#v, want explicit zero", got)
+	}
+	if got := sourceWrite.args[16]; got != QualityReasonStationaryCarry {
+		t.Fatalf("quality reason = %#v, want %q", got, QualityReasonStationaryCarry)
+	}
+}
+
+func TestWriterDoesNotCarryMileageForMovingYutongFrame(t *testing.T) {
+	exec := &recordingExec{}
+	loc := time.FixedZone("Asia/Shanghai", 8*3600)
+	writer := NewWriter(exec, loc)
+	eventTime := time.Date(2026, 7, 19, 8, 0, 0, 0, loc)
+	event := managedTestSource(envelope.FrameEnvelope{
+		Protocol:       envelope.ProtocolYutongMQTT,
+		VIN:            "LMRKH9AC9R1004099",
+		DeviceID:       "LMRKH9AC9R1004099",
+		SourceEndpoint: "mqtt://yutong/ytforward/shln/2",
+		SourceCode:     "yutong",
+		EventTimeMS:    eventTime.UnixMilli(),
+		Fields: map[string]any{
+			"yutong_mqtt.data.latitude":    "30.645438",
+			"yutong_mqtt.data.longitude":   "114.435672",
+			"yutong_mqtt.data.meter_speed": "12",
+		},
+	})
+
+	result, err := writer.AppendWithResult(context.Background(), event)
+	if err != nil {
+		t.Fatalf("AppendWithResult() error = %v", err)
+	}
+	if result.SamplesRecoveredStationary != 0 || result.SamplesWritten != 0 || result.SamplesSkippedMissingMileage != 1 {
+		t.Fatalf("moving frame must remain missing-mileage evidence: %+v", result)
+	}
+	if len(exec.calls) != 1 || !strings.Contains(exec.calls[0].query, "INSERT INTO vehicle_data_source") {
+		t.Fatalf("moving frame writes = %+v, want source touch only", exec.calls)
+	}
+}
+
 func TestWriterAppendWithResultReportsDuplicateMileage(t *testing.T) {
 	exec := &recordingExec{}
 	writer := NewWriter(exec, time.FixedZone("Asia/Shanghai", 8*3600))