功能：完善里程边界与氢耗流式统计

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

@@ -211,12 +211,10 @@ func TestUpsertSourceMileageUsesEventTimeBoundaries(t *testing.T) {
 	}
 }
 
-func TestUpsertSourceMileageAccumulatesOnlyContinuousPureHydrogenIntervals(t *testing.T) {
+func TestUpsertSourceMileageAttributesDeltaToCurrentPureHydrogenMode(t *testing.T) {
 	for _, want := range []string{
 		"pure_hydrogen_mileage_km = pure_hydrogen_mileage_km + CASE",
 		"VALUES(latest_event_time) > latest_event_time",
-		"latest_pure_hydrogen_mode_known = 1",
-		"latest_pure_hydrogen_active = 1",
 		"VALUES(latest_pure_hydrogen_mode_known) = 1",
 		"VALUES(latest_pure_hydrogen_active) = 1",
 		"VALUES(latest_total_mileage_km) - latest_total_mileage_km",
@@ -281,6 +279,26 @@ func TestDailyMileageFromDayBoundaryUsesCurrentMinusPrevious(t *testing.T) {
 	}
 }
 
+func TestIsUsableDailyMileageBoundaryRejectsOlderOfflineGap(t *testing.T) {
+	loc := time.FixedZone("Asia/Shanghai", 8*3600)
+	for _, test := range []struct {
+		name     string
+		baseline time.Time
+		want     bool
+	}{
+		{name: "current day cache", baseline: time.Date(2026, 8, 4, 19, 1, 26, 0, loc), want: true},
+		{name: "previous natural day", baseline: time.Date(2026, 8, 3, 23, 59, 59, 0, loc), want: true},
+		{name: "older offline gap", baseline: time.Date(2026, 5, 21, 23, 13, 2, 0, loc), want: false},
+		{name: "future boundary", baseline: time.Date(2026, 8, 5, 0, 0, 0, 0, loc), want: false},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			if got := IsUsableDailyMileageBoundary("2026-08-04", test.baseline, loc); got != test.want {
+				t.Fatalf("IsUsableDailyMileageBoundary() = %v, want %v", got, test.want)
+			}
+		})
+	}
+}
+
 func TestUpsertSourceMileageSkipsBlankSourceIP(t *testing.T) {
 	exec := &recordingExec{}
 	sample := SourceMileageSample{
@@ -612,6 +630,15 @@ func TestProjectDailyMileageSelectsCandidateAndMarksSource(t *testing.T) {
 		"project": projectFinal,
 		"mark":    markSelected,
 	} {
+		// The project statement also contains an independent day-end odometer
+		// subquery. Check the daily-mileage election order after its main source
+		// FROM clause, rather than mistaking the odometer fallback's freshness
+		// order for the elected daily-distance source order.
+		if queryName == "project" {
+			if index := strings.Index(query, "FROM vehicle_daily_mileage_source s\nLEFT JOIN"); index >= 0 {
+				query = query[index:]
+			}
+		}
 		identityScore := strings.Index(query, "SUM(identity_source.sample_count)")
 		freshness := strings.Index(query, "latest_event_time DESC")
 		rowSamples := strings.LastIndex(query, "sample_count DESC")
@@ -699,3 +726,16 @@ func expectProjectDailyMileageSQL(mock sqlmock.Sqlmock, vin string, statDate str
 		WithArgs(vin, statDate, string(protocol), vin, statDate, string(protocol)).
 		WillReturnResult(sqlmock.NewResult(0, 1))
 }
+
+func TestProjectDailyMileagePersistsIndependentDayEndTotal(t *testing.T) {
+	for _, want := range []string{
+		"day_end_total_mileage_km",
+		"total_candidate.quality_status = 'OK'",
+		"total_candidate.quality_reason, '') = 'gps_coordinate_accumulation'",
+		"day_end_total_mileage_km = VALUES(day_end_total_mileage_km)",
+	} {
+		if !strings.Contains(projectDailyMileageSQL, want) {
+			t.Fatalf("project SQL missing %q:\n%s", want, projectDailyMileageSQL)
+		}
+	}
+}