auto isBusiness based on customer selected

lib/features/operations/blocs/operation_form_cubit.dart

@@ -191,7 +191,6 @@ class OperationFormCubit extends Cubit<OperationFormState> {
   // --- GESTIONE DEI CAMPI IN TEMPO REALE ---
 
   void updateFields({
-    CustomerModel? customer,
     String? reference,
     String? note,
     String? type,
@@ -224,8 +223,6 @@ class OperationFormCubit extends Cubit<OperationFormState> {
     if (quantity != null && quantity > 0) newQuantity = quantity;
 
     final updated = current.copyWith(
-      customer: customer ?? current.customer,
-      customerId: customer?.id ?? current.customerId,
       reference: reference ?? current.reference,
       note: note ?? current.note,
       providerId: clearProvider ? null : (providerId ?? current.providerId),
@@ -254,6 +251,16 @@ class OperationFormCubit extends Cubit<OperationFormState> {
     emit(state.copyWith(operation: updated));
   }
 
+  void updateCustomer(CustomerModel customer) {
+    final bool isBusiness = customer.isBusiness;
+    final updatedOperation = state.operation.copyWith(
+      customer: customer,
+      customerId: customer.id,
+      isBusiness: isBusiness,
+    );
+    emit(state.copyWith(operation: updatedOperation));
+  }
+
   // --- UTILS ---
 
   void setTypeWithSmartDefault(String type) {