feat(stats): store source mileage candidates

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

@@ -29,8 +29,10 @@ type MetricSample struct {
 	Protocol       envelope.Protocol
 	StatDate       string
 	TotalMileageKM float64
+	EventTime      time.Time
 	SourceKey      string
 	Phone          string
+	DeviceID       string
 	SourceEndpoint string
 }
 
@@ -133,25 +135,16 @@ func SamplesFromEnvelope(env envelope.FrameEnvelope, loc *time.Location) ([]Metr
 		Protocol:       env.Protocol,
 		StatDate:       statDate,
 		TotalMileageKM: totalMileage,
+		EventTime:      time.UnixMilli(eventMS).In(loc),
 		SourceKey:      sourceKey(env),
 		Phone:          strings.TrimSpace(env.Phone),
+		DeviceID:       strings.TrimSpace(env.DeviceID),
 		SourceEndpoint: strings.TrimSpace(env.SourceEndpoint),
 	}}, nil
 }
 
 func sourceKey(env envelope.FrameEnvelope) string {
-	parts := []string{
-		strings.TrimSpace(env.Phone),
-		strings.TrimSpace(env.DeviceID),
-		strings.TrimSpace(env.SourceEndpoint),
-	}
-	var kept []string
-	for _, part := range parts {
-		if part != "" {
-			kept = append(kept, part)
-		}
-	}
-	return strings.Join(kept, "@")
+	return SourceKey(env.Protocol, env.Phone, env.DeviceID, NormalizeSourceIP(env.SourceEndpoint))
 }
 
 func isDuplicateColumnError(err error) bool {