fix(go): normalize gb32960 realtime vendor fragments

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

@@ -200,6 +200,77 @@ func TestRepositoryMergesNestedGB32960MotorSlicesBySerialNo(t *testing.T) {
 	}
 }
 
+func TestRepositoryCollapsesGB32960VendorStackFragmentsIntoSingleRealtimeSummary(t *testing.T) {
+	repo, closeFn := newTestRepository(t)
+	defer closeFn()
+	ctx := context.Background()
+
+	first := map[string]any{
+		"engine_work_state":           1,
+		"stack_water_outlet_temp_c":   65,
+		"hydrogen_inlet_pressure_kpa": 130,
+		"cell_count":                  432,
+		"avg_cell_voltage_v":          0.78,
+		"frame_cell_start":            201,
+		"frame_cell_count":            200,
+		"frame_max_cell_voltage_v":    1.0,
+		"frame_min_cell_voltage_v":    0.78,
+	}
+	second := map[string]any{
+		"engine_work_state":           1,
+		"stack_water_outlet_temp_c":   63,
+		"hydrogen_inlet_pressure_kpa": 130,
+		"cell_count":                  432,
+		"avg_cell_voltage_v":          0.80,
+		"frame_cell_start":            401,
+		"frame_cell_count":            32,
+		"frame_max_cell_voltage_v":    1.0,
+		"frame_min_cell_voltage_v":    1.0,
+	}
+	for i, summary := range []map[string]any{first, second} {
+		if err := repo.Update(ctx, envelope.FrameEnvelope{
+			Protocol:     envelope.ProtocolGB32960,
+			VIN:          "VIN001",
+			EventTimeMS:  int64(1000 + i),
+			ReceivedAtMS: int64(1100 + i),
+			Parsed: map[string]any{
+				"data_units": []any{
+					map[string]any{
+						"type": "0x30",
+						"name": "gd_fc_stack",
+						"value": map[string]any{
+							"stack_count": 1,
+							"summaries":   []any{summary},
+						},
+					},
+				},
+			},
+		}); err != nil {
+			t.Fatalf("Update() error = %v", err)
+		}
+	}
+
+	realtimeRaw, err := repo.GetRealtimeRaw(ctx, "VIN001", envelope.ProtocolGB32960)
+	if err != nil {
+		t.Fatalf("GetRealtimeRaw() error = %v", err)
+	}
+	unit := realtimeRaw["data_units"].([]any)[0].(map[string]any)
+	value := unit["value"].(map[string]any)
+	summaries := value["summaries"].([]any)
+	if len(summaries) != 1 {
+		t.Fatalf("stack summaries should be a current stack state, not appended fragments: %#v", summaries)
+	}
+	summary := summaries[0].(map[string]any)
+	for _, fragmentOnly := range []string{"frame_cell_start", "frame_cell_count", "frame_max_cell_voltage_v", "frame_min_cell_voltage_v"} {
+		if _, ok := summary[fragmentOnly]; ok {
+			t.Fatalf("stack summary should not expose fragment-only field %s: %#v", fragmentOnly, summary)
+		}
+	}
+	if summary["stack_water_outlet_temp_c"] != float64(63) {
+		t.Fatalf("summary should keep latest stack-level values: %#v", summary)
+	}
+}
+
 func TestRepositoryReplacesJT808LocationWhenUpdatingRealtimeRaw(t *testing.T) {
 	repo, closeFn := newTestRepository(t)
 	defer closeFn()