cmd: check validate and fix bug risks in commands

cmd/consolidate-kandang-to-farm-stocks/main.go

@@ -729,6 +729,9 @@ func reflowAndRecalculateProductWarehouse(
 	if err != nil {
 		return fmt.Errorf("resolve flag group for product_warehouse %d: %w", productWarehouseID, err)
 	}
+	if flagGroupCode == "" {
+		return nil
+	}
 
 	if _, err := fifoSvc.Reflow(ctx, commonSvc.FifoStockV2ReflowRequest{
 		FlagGroupCode:      flagGroupCode,
@@ -778,6 +781,9 @@ func resolveFlagGroupByProductWarehouse(ctx context.Context, tx *gorm.DB, produc
 		Order("rr.id ASC").
 		Limit(1).
 		Take(&selected).Error
+	if err == gorm.ErrRecordNotFound {
+		return "", nil
+	}
 	if err != nil {
 		return "", err
 	}