fix(stats): project trusted mileage source endpoint from metadata

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

@@ -102,8 +102,9 @@ func TestProjectDailyMileageSelectsCandidateAndMarksSource(t *testing.T) {
 		"FROM vehicle_daily_mileage_source s",
 		"LEFT JOIN vehicle_data_source ds",
 		"ORDER BY COALESCE(ds.trust_priority, 100)",
-		"s.quality_status = 'OK'",
+		"s.quality_status = '" + QualityOK + "'",
 		"s.daily_mileage_km BETWEEN 0 AND",
+		"COALESCE(NULLIF(ds.latest_source_endpoint, ''), s.source_endpoint)",
 	} {
 		if !strings.Contains(projectFinal, want) {
 			t.Fatalf("project query missing %q: %s", want, projectFinal)