fix(go): normalize history parsed field names

go/vehicle-gateway/internal/realtime/kv.go

@@ -27,7 +27,7 @@ func BuildFieldsEnvelope(env envelope.FrameEnvelope) (envelope.FrameEnvelope, bo
 		return envelope.FrameEnvelope{}, false
 	}
 	rows := realtimeKVFields(env, env.Parsed)
-	fields := make(map[string]any, len(rows)+len(env.Fields))
+	fields := make(map[string]any, len(rows))
 	for _, row := range rows {
 		key := row.Domain
 		if strings.TrimSpace(row.Field) != "" {
@@ -35,11 +35,6 @@ func BuildFieldsEnvelope(env envelope.FrameEnvelope) (envelope.FrameEnvelope, bo
 		}
 		fields[key] = row.Value
 	}
-	for key, value := range env.Fields {
-		if strings.TrimSpace(key) != "" {
-			fields[key] = value
-		}
-	}
 	if len(fields) == 0 {
 		return envelope.FrameEnvelope{}, false
 	}

go/vehicle-gateway/internal/realtime/kv_test.go

@@ -39,6 +39,48 @@ func TestRealtimeKVFieldsFromGB32960ParsedDomains(t *testing.T) {
 	}
 }
 
+func TestBuildFieldsEnvelopeUsesOnlyMappedFieldNames(t *testing.T) {
+	fieldsEnv, ok := BuildFieldsEnvelope(envelope.FrameEnvelope{
+		Protocol:     envelope.ProtocolGB32960,
+		VIN:          "VIN001",
+		MessageID:    "0x02",
+		EventTimeMS:  1000,
+		ReceivedAtMS: 1100,
+		EventID:      "event-1",
+		Fields: map[string]any{
+			"charge_status":              1,
+			envelope.FieldSOCPercent:     88.0,
+			envelope.FieldTotalMileageKM: 100.1,
+		},
+		Parsed: map[string]any{
+			"data_units": []any{
+				map[string]any{"type": "0x01", "name": "vehicle", "value": map[string]any{
+					"charge_status":    1,
+					"soc_percent":      88.0,
+					"total_mileage_km": 100.1,
+				}},
+			},
+		},
+	})
+	if !ok {
+		t.Fatal("BuildFieldsEnvelope() should emit mapped fields")
+	}
+	for _, bareKey := range []string{"charge_status", "soc_percent", "total_mileage_km"} {
+		if _, exists := fieldsEnv.Fields[bareKey]; exists {
+			t.Fatalf("fields envelope should not expose bare env.Fields key %q: %#v", bareKey, fieldsEnv.Fields)
+		}
+	}
+	for _, mappedKey := range []string{
+		"gb32960.vehicle.charge_status",
+		"gb32960.vehicle.soc_percent",
+		"gb32960.vehicle.total_mileage_km",
+	} {
+		if _, exists := fieldsEnv.Fields[mappedKey]; !exists {
+			t.Fatalf("fields envelope missing mapped key %q: %#v", mappedKey, fieldsEnv.Fields)
+		}
+	}
+}
+
 func TestRealtimeKVFieldsFromJT808ParsedFields(t *testing.T) {
 	jtRows := realtimeKVFields(envelope.FrameEnvelope{
 		Protocol: envelope.ProtocolJT808,