fix: API 응답 파싱 오류 수정 및 에러 처리 개선

주요 변경사항:
- 창고 관리 API 응답 구조와 DTO 불일치 수정
  - WarehouseLocationDto에 code, manager_phone 필드 추가
  - RemoteDataSource에서 API 응답을 DTO 구조에 맞게 변환
- 회사 관리 API 응답 파싱 오류 수정
  - CompanyResponse의 필수 필드를 nullable로 변경
  - PaginatedResponse 구조 매핑 로직 개선
- 에러 처리 및 로깅 개선
  - Service Layer에 상세 에러 로깅 추가
  - Controller에서 에러 타입별 처리
- 새로운 유틸리티 추가
  - ResponseInterceptor: API 응답 정규화
  - DebugLogger: 디버깅 도구
  - HealthCheckService: 서버 상태 확인
- 문서화
  - API 통합 테스트 가이드
  - 에러 분석 보고서
  - 리팩토링 계획서

lib/data/models/equipment/equipment_request.freezed.dart

@@ -389,6 +389,7 @@ mixin _$UpdateEquipmentRequest {
   String? get barcode => throw _privateConstructorUsedError;
   DateTime? get purchaseDate => throw _privateConstructorUsedError;
   double? get purchasePrice => throw _privateConstructorUsedError;
+  @EquipmentStatusJsonConverter()
   String? get status => throw _privateConstructorUsedError;
   int? get currentCompanyId => throw _privateConstructorUsedError;
   int? get currentBranchId => throw _privateConstructorUsedError;
@@ -423,7 +424,7 @@ abstract class $UpdateEquipmentRequestCopyWith<$Res> {
       String? barcode,
       DateTime? purchaseDate,
       double? purchasePrice,
-      String? status,
+      @EquipmentStatusJsonConverter() String? status,
       int? currentCompanyId,
       int? currentBranchId,
       int? warehouseLocationId,
@@ -553,7 +554,7 @@ abstract class _$$UpdateEquipmentRequestImplCopyWith<$Res>
       String? barcode,
       DateTime? purchaseDate,
       double? purchasePrice,
-      String? status,
+      @EquipmentStatusJsonConverter() String? status,
       int? currentCompanyId,
       int? currentBranchId,
       int? warehouseLocationId,
@@ -676,7 +677,7 @@ class _$UpdateEquipmentRequestImpl implements _UpdateEquipmentRequest {
       this.barcode,
       this.purchaseDate,
       this.purchasePrice,
-      this.status,
+      @EquipmentStatusJsonConverter() this.status,
       this.currentCompanyId,
       this.currentBranchId,
       this.warehouseLocationId,
@@ -706,6 +707,7 @@ class _$UpdateEquipmentRequestImpl implements _UpdateEquipmentRequest {
   @override
   final double? purchasePrice;
   @override
+  @EquipmentStatusJsonConverter()
   final String? status;
   @override
   final int? currentCompanyId;
@@ -810,7 +812,7 @@ abstract class _UpdateEquipmentRequest implements UpdateEquipmentRequest {
       final String? barcode,
       final DateTime? purchaseDate,
       final double? purchasePrice,
-      final String? status,
+      @EquipmentStatusJsonConverter() final String? status,
       final int? currentCompanyId,
       final int? currentBranchId,
       final int? warehouseLocationId,
@@ -840,6 +842,7 @@ abstract class _UpdateEquipmentRequest implements UpdateEquipmentRequest {
   @override
   double? get purchasePrice;
   @override
+  @EquipmentStatusJsonConverter()
   String? get status;
   @override
   int? get currentCompanyId;