feat(frontend): 승인 템플릿 API 통합 및 디버그 로그인 확장

- docs 폴더 문서를 최신 API 계약으로 갱신하고 가이드를 다듬었다\n- approvals data/presentation 레이어를 API v4 스펙에 맞춰 리팩터링했다\n- approver 자동완성 위젯을 신규 공유 레포지토리에 맞춰 교체하고 UX를 보강했다\n- inventory/rental 페이지 테이블 초기화 시 승인 기준 연동을 정비했다\n- 로그인 페이지 디버그 버튼을 tera/exa 계정으로 분리해 QA 로그인을 단순화했다\n- get_it 등록과 테스트 케이스를 신규 공유 리포지토리에 맞춰 업데이트했다

lib/features/approvals/shared/data/repositories/approval_approver_repository_remote.dart

@@ -0,0 +1,84 @@
+import 'package:dio/dio.dart';
+
+import '../../../../../core/network/api_client.dart';
+import '../../../../../core/network/api_routes.dart';
+import '../../domain/entities/approval_approver_candidate.dart';
+import '../../domain/repositories/approval_approver_repository.dart';
+import '../dtos/approval_approver_candidate_dto.dart';
+
+/// 승인자 자동완성용 원격 저장소 구현체.
+class ApprovalApproverRepositoryRemote implements ApprovalApproverRepository {
+  ApprovalApproverRepositoryRemote({required ApiClient apiClient})
+    : _api = apiClient;
+
+  final ApiClient _api;
+
+  static const _basePath = '${ApiRoutes.apiV1}/users';
+
+  @override
+  Future<List<ApprovalApproverCandidate>> search({
+    required String keyword,
+    int limit = 20,
+  }) async {
+    final trimmed = keyword.trim();
+    if (trimmed.isEmpty) {
+      return const [];
+    }
+
+    final response = await _api.get<Map<String, dynamic>>(
+      _basePath,
+      query: _buildQuery(limit: limit, keyword: trimmed),
+      options: Options(responseType: ResponseType.json),
+    );
+
+    return _mapCandidates(response.data);
+  }
+
+  @override
+  Future<ApprovalApproverCandidate?> fetchById(int id) async {
+    final response = await _api.get<Map<String, dynamic>>(
+      '$_basePath/$id',
+      query: ApiClient.buildQuery(include: const ['group']),
+      options: Options(responseType: ResponseType.json),
+    );
+
+    final payload = _api.unwrapAsMap(response);
+    if (payload.isEmpty) {
+      return null;
+    }
+    return ApprovalApproverCandidateDto.fromJson(payload).toEntity();
+  }
+
+  @override
+  Future<List<ApprovalApproverCandidate>> listInitial({int limit = 20}) async {
+    final response = await _api.get<Map<String, dynamic>>(
+      _basePath,
+      query: _buildQuery(limit: limit),
+      options: Options(responseType: ResponseType.json),
+    );
+
+    return _mapCandidates(response.data);
+  }
+
+  Map<String, dynamic> _buildQuery({required int limit, String? keyword}) {
+    return ApiClient.buildQuery(
+      page: 1,
+      pageSize: limit,
+      q: keyword,
+      sort: 'name',
+      order: 'asc',
+      include: const ['group'],
+      filters: const {'is_active': true},
+    );
+  }
+
+  List<ApprovalApproverCandidate> _mapCandidates(
+    Map<String, dynamic>? payload,
+  ) {
+    return (payload?['items'] as List<dynamic>? ?? const [])
+        .whereType<Map<String, dynamic>>()
+        .map(ApprovalApproverCandidateDto.fromJson)
+        .map((dto) => dto.toEntity())
+        .toList(growable: false);
+  }
+}