feat(dashboard): 결재 역할 뱃지와 문서 정합성 반영

- doc/frontend_backend_alignment_report.md에 roles 필터 적용 배경과 UI 반영 사항을 기록

- lib/features/dashboard/data/dashboard_summary_dto.dart에서 roles 파싱과 enum 매핑 로직, 문자열 리스트 util 추가

- lib/features/dashboard/domain/entities/dashboard_pending_approval.dart에 역할 enum과 도메인 필드 추가

- lib/features/dashboard/presentation/pages/dashboard_page.dart에서 결재 카드 헤더/설명 수정 및 역할 뱃지 렌더링 지원

- test/features/dashboard/data/dashboard_summary_dto_test.dart 신규 작성해 DTO→도메인 매핑과 무시 케이스를 검증

- test/features/masters/user/presentation/pages/user_page_test.dart에서 사용되지 않는 PermissionManager import 제거

lib/features/dashboard/data/dtos/dashboard_summary_dto.dart

@@ -141,6 +141,7 @@ class DashboardApprovalDto {
     required this.title,
     required this.stepSummary,
     this.requestedAt,
+    this.roles = const [],
   });
 
   final int? approvalId;
@@ -148,6 +149,7 @@ class DashboardApprovalDto {
   final String title;
   final String stepSummary;
   final DateTime? requestedAt;
+  final List<String> roles;
 
   factory DashboardApprovalDto.fromJson(Map<String, dynamic> json) {
     num? rawId = _readNum(json, 'approval_id');
@@ -176,16 +178,22 @@ class DashboardApprovalDto {
       title: _readString(json, 'title') ?? '',
       stepSummary: _readString(json, 'step_summary') ?? '',
       requestedAt: _parseDate(json['requested_at']),
+      roles: _readStringList(json, 'roles'),
     );
   }
 
   DashboardPendingApproval toEntity() {
+    final parsedRoles = roles
+        .map(DashboardApprovalRole.fromName)
+        .whereType<DashboardApprovalRole>()
+        .toList(growable: false);
     return DashboardPendingApproval(
       approvalId: approvalId,
       approvalNo: approvalNo,
       title: title,
       stepSummary: stepSummary,
       requestedAt: requestedAt,
+      roles: parsedRoles,
     );
   }
 }
@@ -233,3 +241,25 @@ double? _readDouble(Map<String, dynamic>? source, String key) {
   }
   return value.toDouble();
 }
+
+List<String> _readStringList(Map<String, dynamic>? source, String key) {
+  if (source == null) {
+    return const [];
+  }
+  final value = source[key];
+  if (value is List) {
+    return value
+        .whereType<String>()
+        .map((text) => text.trim())
+        .where((text) => text.isNotEmpty)
+        .toList(growable: false);
+  }
+  if (value is String) {
+    final normalized = value.trim();
+    if (normalized.isEmpty) {
+      return const [];
+    }
+    return [normalized];
+  }
+  return const [];
+}