update

pkg/cart/mutation_remove_item.go

@@ -22,7 +22,7 @@ import (
 //   - If multiple lines somehow shared the same Id (should not happen), only
 //     the first match would be removed—data integrity relies on unique line Ids.
 
-func RemoveItem(g *CartGrain, m *messages.RemoveItem) error {
+func (c *CartMutationContext) RemoveItem(g *CartGrain, m *messages.RemoveItem) error {
 	if m == nil {
 		return fmt.Errorf("RemoveItem: nil payload")
 	}