결재 및 마스터 모듈을 v4 API 계약에 맞게 조정

lib/features/masters/customer/domain/entities/customer.dart

@@ -4,6 +4,7 @@ class Customer {
     this.id,
     required this.customerCode,
     required this.customerName,
+    this.contactName,
     this.isPartner = false,
     this.isGeneral = true,
     this.email,
@@ -20,6 +21,7 @@ class Customer {
   final int? id;
   final String customerCode;
   final String customerName;
+  final String? contactName;
   final bool isPartner;
   final bool isGeneral;
   final String? email;
@@ -37,6 +39,7 @@ class Customer {
     int? id,
     String? customerCode,
     String? customerName,
+    String? contactName,
     bool? isPartner,
     bool? isGeneral,
     String? email,
@@ -53,6 +56,7 @@ class Customer {
       id: id ?? this.id,
       customerCode: customerCode ?? this.customerCode,
       customerName: customerName ?? this.customerName,
+      contactName: contactName ?? this.contactName,
       isPartner: isPartner ?? this.isPartner,
       isGeneral: isGeneral ?? this.isGeneral,
       email: email ?? this.email,
@@ -88,6 +92,7 @@ class CustomerInput {
   CustomerInput({
     required this.customerCode,
     required this.customerName,
+    this.contactName,
     required this.isPartner,
     required this.isGeneral,
     this.email,
@@ -100,6 +105,7 @@ class CustomerInput {
 
   final String customerCode;
   final String customerName;
+  final String? contactName;
   final bool isPartner;
   final bool isGeneral;
   final String? email;
@@ -114,6 +120,7 @@ class CustomerInput {
     return {
       'customer_code': customerCode,
       'customer_name': customerName,
+      'contact_name': contactName,
       'is_partner': isPartner,
       'is_general': isGeneral,
       'email': email,