결재 템플릿 단계 적용 구현

- ApprovalTemplate 엔티티·DTO·원격 리포지토리 추가
- ApprovalController에 템플릿 로딩/적용 상태와 assignSteps 호출 연동
- ApprovalPage 단계 탭에 템플릿 선택 UI 및 적용 확인 다이얼로그 구현
- 템플릿 적용 단위 테스트와 IMPLEMENTATION_TASKS 현황 갱신

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

@@ -0,0 +1,119 @@
+/// 메뉴 엔티티
+///
+/// - 계층 구조를 표현하기 위해 상위 메뉴 정보를 포함한다.
+/// - presentation/data 레이어 세부 구현에 의존하지 않는다.
+class MenuItem {
+  MenuItem({
+    this.id,
+    required this.menuCode,
+    required this.menuName,
+    this.parent,
+    this.path,
+    this.displayOrder,
+    this.isActive = true,
+    this.isDeleted = false,
+    this.note,
+    this.createdAt,
+    this.updatedAt,
+  });
+
+  /// PK (null 이면 신규 생성)
+  final int? id;
+
+  /// 메뉴 코드 (고유)
+  final String menuCode;
+
+  /// 메뉴명
+  final String menuName;
+
+  /// 상위 메뉴 정보
+  final MenuSummary? parent;
+
+  /// 라우트 경로
+  final String? path;
+
+  /// 표시 순서
+  final int? displayOrder;
+
+  /// 사용 여부
+  final bool isActive;
+
+  /// 소프트 삭제 여부
+  final bool isDeleted;
+
+  /// 비고
+  final String? note;
+
+  /// 생성/수정 일시
+  final DateTime? createdAt;
+  final DateTime? updatedAt;
+
+  MenuItem copyWith({
+    int? id,
+    String? menuCode,
+    String? menuName,
+    MenuSummary? parent,
+    String? path,
+    int? displayOrder,
+    bool? isActive,
+    bool? isDeleted,
+    String? note,
+    DateTime? createdAt,
+    DateTime? updatedAt,
+  }) {
+    return MenuItem(
+      id: id ?? this.id,
+      menuCode: menuCode ?? this.menuCode,
+      menuName: menuName ?? this.menuName,
+      parent: parent ?? this.parent,
+      path: path ?? this.path,
+      displayOrder: displayOrder ?? this.displayOrder,
+      isActive: isActive ?? this.isActive,
+      isDeleted: isDeleted ?? this.isDeleted,
+      note: note ?? this.note,
+      createdAt: createdAt ?? this.createdAt,
+      updatedAt: updatedAt ?? this.updatedAt,
+    );
+  }
+}
+
+/// 상위 메뉴 요약 정보
+class MenuSummary {
+  MenuSummary({required this.id, required this.menuName});
+
+  final int id;
+  final String menuName;
+}
+
+/// 메뉴 생성/수정 입력 모델
+class MenuInput {
+  MenuInput({
+    required this.menuCode,
+    required this.menuName,
+    this.parentMenuId,
+    this.path,
+    this.displayOrder,
+    this.isActive = true,
+    this.note,
+  });
+
+  final String menuCode;
+  final String menuName;
+  final int? parentMenuId;
+  final String? path;
+  final int? displayOrder;
+  final bool isActive;
+  final String? note;
+
+  Map<String, dynamic> toPayload() {
+    return {
+      'menu_code': menuCode,
+      'menu_name': menuName,
+      'parent_menu_id': parentMenuId,
+      'path': path,
+      'display_order': displayOrder,
+      'is_active': isActive,
+      'note': note,
+    };
+  }
+}