feat: 아이템 카테고리 정보 REST API 구현

[dev-ant]

📋 상세 설명

• 아이템 상위 카테고리, 하위 카테고리 데이터를 반환하는 API 구현
  • ItemCategory는 개수가 적고, 변동도 적어 DB가 아닌 Enum으로 관리.

📊 체크리스트

• PR 제목이 형식에 맞나요 e.g. feat: PR을 등록한다
• 코드가 테스트 되었나요
• 문서는 업데이트 되었나요
• 불필요한 코드를 제거했나요
• 이슈와 라벨이 등록되었나요

📆 마감일

Close #48

[Copilot]

Pull Request Overview

This PR implements a REST API for retrieving item category information, including top-level and sub-category data. The implementation uses enums to manage ItemCategory data instead of database storage due to the small and infrequently changing dataset.

Key changes:

• Added ItemCategoryResponse DTO to structure category data
• Created ItemController with /api/items/categories endpoint
• Implemented ItemService to handle category retrieval logic

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/main/java/until/the/eternity/item/interfaces/rest/dto/ItemCategoryResponse.java	New DTO for category response structure with static factory method
src/main/java/until/the/eternity/item/interfaces/rest/controller/ItemController.java	New REST controller providing category information endpoint
src/main/java/until/the/eternity/item/application/service/ItemService.java	New service layer for item-related operations
src/main/java/until/the/eternity/itemoption/domain/entity/ItemOption.java	Minor comment formatting cleanup
src/test/java/until/the/eternity/auctionhistory/application/service/persister/AuctionHistoryPersisterTest.java	Import statement reorganization
src/test/java/until/the/eternity/auctionhistory/application/service/fetcher/AuctionHistoryFetcherTest.java	Import statement reorganization
src/test/java/until/the/eternity/auctionhistory/application/service/AuctionHistoryServiceTest.java	Import statement reorganization

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

Consider using .toList() instead of .collect(Collectors.toList()) for better performance and readability in Java 16+.

[github-actions]

✅ 테스트 결과 for PR

Build: success

🧪 테스트 실행 with Gradle
📈 Coverage: -0.00%

📁 테스트 결과
📁 커버리지 보고서 (HTML)

[codecov]

Codecov Report

❌ Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...tem/interfaces/rest/controller/ItemController.java	0.00%	2 Missing ⚠️
...eternity/item/application/service/ItemService.java	0.00%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!