fix(billing): fix review comment

Author: borbelyr-kong

openmeter/billing/service/invoicecalc/taxconfig_test.go

@@ -133,8 +133,8 @@ func TestSnapshotTaxConfigIntoLines(t *testing.T) {
 					Stripe: &productcatalog.StripeTaxConfig{Code: "txcd_10000000"},
 				}),
 			),
-			deps:   StandardInvoiceCalculatorDependencies{TaxCodes: TaxCodes{"txcd_10000000": tc1}},
-			wantTC: &billing.TaxConfig{TaxConfig: productcatalog.TaxConfig{Stripe: &productcatalog.StripeTaxConfig{Code: "txcd_10000000"}}},
+			deps:      StandardInvoiceCalculatorDependencies{TaxCodes: TaxCodes{"txcd_10000000": tc1}},
+			wantTC:    &billing.TaxConfig{TaxConfig: productcatalog.TaxConfig{Stripe: &productcatalog.StripeTaxConfig{Code: "txcd_10000000"}}},
 			wantNoErr: true,
 		},
 		{

openmeter/taxcode/taxcode.go

@@ -87,7 +87,8 @@ type TaxCode struct {
 }
 
 // Equal returns true when both TaxCode values carry identical semantic data.
-// ManagedModel timestamps (CreatedAt, UpdatedAt, DeletedAt) are excluded; all other fields are compared.
+// Compares ID, Namespace, Key, Name, Description, and AppMappings.
+// ManagedModel timestamps, Metadata, and Annotations are excluded.
 func (t *TaxCode) Equal(v *TaxCode) bool {
 	if t == nil && v == nil {
 		return true