feat: 회사 관리 API 연동 구현

- CompanyService 및 RemoteDataSource 구현
- Company, Branch DTO 모델 생성 (Freezed)
- 의존성 주입 컨테이너 업데이트
- 회사 등록/수정 폼에 API 연동 로직 적용
- API 통합 계획 문서 업데이트

lib/data/models/company/branch_dto.g.dart

@@ -0,0 +1,102 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'branch_dto.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+_$CreateBranchRequestImpl _$$CreateBranchRequestImplFromJson(
+        Map<String, dynamic> json) =>
+    _$CreateBranchRequestImpl(
+      branchName: json['branch_name'] as String,
+      address: json['address'] as String,
+      phone: json['phone'] as String,
+      managerName: json['manager_name'] as String?,
+      managerPhone: json['manager_phone'] as String?,
+      remark: json['remark'] as String?,
+    );
+
+Map<String, dynamic> _$$CreateBranchRequestImplToJson(
+        _$CreateBranchRequestImpl instance) =>
+    <String, dynamic>{
+      'branch_name': instance.branchName,
+      'address': instance.address,
+      'phone': instance.phone,
+      'manager_name': instance.managerName,
+      'manager_phone': instance.managerPhone,
+      'remark': instance.remark,
+    };
+
+_$UpdateBranchRequestImpl _$$UpdateBranchRequestImplFromJson(
+        Map<String, dynamic> json) =>
+    _$UpdateBranchRequestImpl(
+      branchName: json['branch_name'] as String?,
+      address: json['address'] as String?,
+      phone: json['phone'] as String?,
+      managerName: json['manager_name'] as String?,
+      managerPhone: json['manager_phone'] as String?,
+      remark: json['remark'] as String?,
+    );
+
+Map<String, dynamic> _$$UpdateBranchRequestImplToJson(
+        _$UpdateBranchRequestImpl instance) =>
+    <String, dynamic>{
+      'branch_name': instance.branchName,
+      'address': instance.address,
+      'phone': instance.phone,
+      'manager_name': instance.managerName,
+      'manager_phone': instance.managerPhone,
+      'remark': instance.remark,
+    };
+
+_$BranchResponseImpl _$$BranchResponseImplFromJson(Map<String, dynamic> json) =>
+    _$BranchResponseImpl(
+      id: (json['id'] as num).toInt(),
+      companyId: (json['company_id'] as num).toInt(),
+      branchName: json['branch_name'] as String,
+      address: json['address'] as String,
+      phone: json['phone'] as String,
+      managerName: json['manager_name'] as String?,
+      managerPhone: json['manager_phone'] as String?,
+      remark: json['remark'] as String?,
+      createdAt: DateTime.parse(json['created_at'] as String),
+      updatedAt: DateTime.parse(json['updated_at'] as String),
+      addressId: (json['address_id'] as num?)?.toInt(),
+    );
+
+Map<String, dynamic> _$$BranchResponseImplToJson(
+        _$BranchResponseImpl instance) =>
+    <String, dynamic>{
+      'id': instance.id,
+      'company_id': instance.companyId,
+      'branch_name': instance.branchName,
+      'address': instance.address,
+      'phone': instance.phone,
+      'manager_name': instance.managerName,
+      'manager_phone': instance.managerPhone,
+      'remark': instance.remark,
+      'created_at': instance.createdAt.toIso8601String(),
+      'updated_at': instance.updatedAt.toIso8601String(),
+      'address_id': instance.addressId,
+    };
+
+_$BranchListDtoImpl _$$BranchListDtoImplFromJson(Map<String, dynamic> json) =>
+    _$BranchListDtoImpl(
+      id: (json['id'] as num).toInt(),
+      companyId: (json['company_id'] as num).toInt(),
+      branchName: json['branch_name'] as String,
+      address: json['address'] as String,
+      phone: json['phone'] as String,
+      managerName: json['manager_name'] as String?,
+    );
+
+Map<String, dynamic> _$$BranchListDtoImplToJson(_$BranchListDtoImpl instance) =>
+    <String, dynamic>{
+      'id': instance.id,
+      'company_id': instance.companyId,
+      'branch_name': instance.branchName,
+      'address': instance.address,
+      'phone': instance.phone,
+      'manager_name': instance.managerName,
+    };