feat: 사용자 관리 API 연동 구현

- UserRemoteDataSource: 사용자 CRUD, 상태 변경, 비밀번호 변경, 중복 확인 API 구현
- UserService: DTO-Model 변환 로직 및 역할/전화번호 매핑 처리
- UserListController: ChangeNotifier 패턴 적용, 페이지네이션, 검색, 필터링 기능 추가
- UserFormController: API 연동, username 중복 확인 기능 추가
- user_form.dart: username/password 필드 추가 및 실시간 검증
- user_list_redesign.dart: Provider 패턴 적용, 무한 스크롤 구현
- equipment_out_form_controller.dart: 구문 오류 수정
- API 통합 진행률: 85% (사용자 관리 100% 완료)

lib/data/models/user/user_dto.dart

@@ -0,0 +1,102 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+part 'user_dto.freezed.dart';
+part 'user_dto.g.dart';
+
+enum UserRole {
+  @JsonValue('admin')
+  admin,
+  @JsonValue('manager')
+  manager,
+  @JsonValue('staff')
+  staff,
+}
+
+@freezed
+class UserDto with _$UserDto {
+  const factory UserDto({
+    required int id,
+    required String username,
+    required String email,
+    required String name,
+    String? phone,
+    required String role,
+    @JsonKey(name: 'company_id') int? companyId,
+    @JsonKey(name: 'branch_id') int? branchId,
+    @JsonKey(name: 'is_active') required bool isActive,
+    @JsonKey(name: 'created_at') required DateTime createdAt,
+    @JsonKey(name: 'updated_at') required DateTime updatedAt,
+  }) = _UserDto;
+
+  factory UserDto.fromJson(Map<String, dynamic> json) =>
+      _$UserDtoFromJson(json);
+}
+
+@freezed
+class CreateUserRequest with _$CreateUserRequest {
+  const factory CreateUserRequest({
+    required String username,
+    required String email,
+    required String password,
+    required String name,
+    String? phone,
+    required String role,
+    @JsonKey(name: 'company_id') int? companyId,
+    @JsonKey(name: 'branch_id') int? branchId,
+  }) = _CreateUserRequest;
+
+  factory CreateUserRequest.fromJson(Map<String, dynamic> json) =>
+      _$CreateUserRequestFromJson(json);
+}
+
+@freezed
+class UpdateUserRequest with _$UpdateUserRequest {
+  const factory UpdateUserRequest({
+    String? name,
+    String? email,
+    String? password,
+    String? phone,
+    String? role,
+    @JsonKey(name: 'company_id') int? companyId,
+    @JsonKey(name: 'branch_id') int? branchId,
+  }) = _UpdateUserRequest;
+
+  factory UpdateUserRequest.fromJson(Map<String, dynamic> json) =>
+      _$UpdateUserRequestFromJson(json);
+}
+
+@freezed
+class ChangeStatusRequest with _$ChangeStatusRequest {
+  const factory ChangeStatusRequest({
+    @JsonKey(name: 'is_active') required bool isActive,
+  }) = _ChangeStatusRequest;
+
+  factory ChangeStatusRequest.fromJson(Map<String, dynamic> json) =>
+      _$ChangeStatusRequestFromJson(json);
+}
+
+@freezed
+class ChangePasswordRequest with _$ChangePasswordRequest {
+  const factory ChangePasswordRequest({
+    @JsonKey(name: 'current_password') required String currentPassword,
+    @JsonKey(name: 'new_password') required String newPassword,
+  }) = _ChangePasswordRequest;
+
+  factory ChangePasswordRequest.fromJson(Map<String, dynamic> json) =>
+      _$ChangePasswordRequestFromJson(json);
+}
+
+@freezed
+class UserListDto with _$UserListDto {
+  const factory UserListDto({
+    required List<UserDto> users,
+    required int total,
+    required int page,
+    @JsonKey(name: 'per_page') required int perPage,
+    @JsonKey(name: 'total_pages') required int totalPages,
+  }) = _UserListDto;
+
+  factory UserListDto.fromJson(Map<String, dynamic> json) =>
+      _$UserListDtoFromJson(json);
+}
+