Add guidelines for third-party package selection. サードパーティパッケージの選定ガイドラインを追加.

.github/copilot-instructions.md

@@ -0,0 +1,46 @@
+# Copilot Instructions for Lepus Development Guidelines
+
+This repository contains the engineering team's documentation standards, review policies, and PR templates. It is **documentation-only**—no code or build/test automation is present.
+
+## Key Knowledge for AI Agents
+
+### 1. Repository Purpose & Scope
+- **Internal use only**: PRs from outside Lepus Group are not accepted.
+- All content is for documentation, not code implementation.
+- Main files: `README.md`, `README.ja.md`, `CONTRIBUTING.md`, `docs/en/REVIEW_POLICY.md`, `docs/ja/REVIEW_POLICY.md`, PR templates in `docs/en/` and `docs/ja/`.
+
+### 2. Pull Request Workflow
+- **Branch from `main`** for changes.
+- Use the PR template (`docs/en/PULL_REQUEST_TEMPLATE.md` or `docs/ja/PULL_REQUEST_TEMPLATE.md`).
+- PRs must include:
+  - Background/purpose (ticket link, rationale)
+  - Main changes (bulleted)
+  - Acceptance criteria (checklist)
+  - Impacted packages/areas
+  - Test evidence (screenshots, CI results, reproduction steps)
+- **No external PRs**—fork if you wish to adapt.
+
+### 3. Review Policy Highlights
+- **Review levels**:
+  - L0: Minor fix (light check, focus on CI/tests)
+  - L1: Feature addition/modification (AC & evidence required)
+  - L2: High-risk (schema/security/external integration) → Pair review + manual verification
+- **Mandatory**: Acceptance criteria, test results, and reproduction steps.
+- **Commit conventions**: Use `test:`, `fix:`, `refactor:` prefixes. Large renames/formatting → separate PRs.
+- **Explicit impact scope**: Always state affected areas (API/DB/auth/UI/external systems).
+
+### 4. Patterns & Conventions
+- **Single Responsibility Principle**: Bug fixes and refactoring should be separate PRs (except minimal, behavior-preserving refactoring).
+- **RACI matrix**: Developer (implementation/tests), Reviewer/Tech Lead (quality/design/risk), QA/PM (AC definition/validation).
+- **Test-first for bug fixes**: Reproduction test → fix → regression check.
+
+### 5. Language & Documentation
+- All documentation is available in both English (`docs/en/`) and Japanese (`docs/ja/`).
+- Reference the appropriate language version for PRs and reviews.
+
+## Examples
+- See `docs/en/REVIEW_POLICY.md` and `docs/ja/REVIEW_POLICY.md` for detailed review criteria and RACI roles.
+- See PR templates for required sections and checklists.
+
+---
+For questions or unclear conventions, consult `README.md` or open an issue for clarification.

.gitignore

@@ -0,0 +1,23 @@
+# macOS system files
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# macOS folder attributes
+._*
+
+# macOS Trash
+.Trashes
+
+# macOS Spotlight files
+.Spotlight-V100
+
+# macOS volume files
+.VolumeIcon.icns
+
+# macOS Finder files
+.fseventsd
+
+# VSCode settings and workspace files
+.vscode/
+*.code-workspace

README.ja.md

@@ -1,50 +1,68 @@
 # LEPUS 開発ガイドライン ![version](https://img.shields.io/badge/バージョン-1.0-blue)
 
+🇯🇵 **日本語** | 🇺🇸 [English](README.md)
+
 このリポジトリには、**レプスグループ エンジニアリングチームの開発ガイドラインとベストプラクティス** が含まれています。  
 コードレビュー、プルリクエスト、テスト、チームコラボレーションに関する原則を定義しています。
 
 ---
 
 ## 📖 利用可能なドキュメント
 
-- [レビューポリシー (日本語)](docs/ja/REVIEW_POLICY.md)
-  - [PR単位の原則](docs/ja/REVIEW_POLICY.md#pr単位の原則)
+- [レビューポリシー](docs/ja/REVIEW_POLICY.md)
+  - [PR 単位の原則](docs/ja/REVIEW_POLICY.md#pr単位の原則)
   - [レビューの心得](docs/ja/REVIEW_POLICY.md#-レビューの心得)
   - [簡易チェックリスト](docs/ja/REVIEW_POLICY.md#-簡易チェックリスト)
   - [レベル判定ガイド](docs/ja/REVIEW_POLICY.md#-レベル判定ガイド)
-  - [RACIマトリクス](docs/ja/REVIEW_POLICY.md#-raciマトリクス)
-- [Review Policy (English)](docs/en/REVIEW_POLICY.md)
-  - [PR Size Guidelines](docs/en/REVIEW_POLICY.md#pr-size-guidelines)
-  - [Review Mindset](docs/en/REVIEW_POLICY.md#-review-mindset)
-  - [Quick Checklist](docs/en/REVIEW_POLICY.md#-quick-checklist)
-  - [Level Decision Guide](docs/en/REVIEW_POLICY.md#-level-decision-guide)
-  - [RACI Matrix](docs/en/REVIEW_POLICY.md#-raci-matrix)
-- [プルリクエストテンプレート (日本語)](docs/ja/PULL_REQUEST_TEMPLATE.md)
+  - [RACI マトリクス](docs/ja/REVIEW_POLICY.md#-raciマトリクス)
+- [プルリクエストテンプレート](docs/ja/PULL_REQUEST_TEMPLATE.md)
   - [テスト証跡](docs/ja/PULL_REQUEST_TEMPLATE.md#-テスト証跡)
   - [チェックリスト](docs/ja/PULL_REQUEST_TEMPLATE.md#-チェックリスト)
-- [Pull Request Template (English)](docs/en/PULL_REQUEST_TEMPLATE.md)
-  - [Test Evidence](docs/en/PULL_REQUEST_TEMPLATE.md#-test-evidence)
-  - [Checklist](docs/en/PULL_REQUEST_TEMPLATE.md#-checklist)
+- [サードパーティパッケージ選定基準](docs/ja/DEPENDENCIES_GUIDELINES.md)
+  - [目的](docs/ja/DEPENDENCIES_GUIDELINES.md#目的)
+  - [信頼性](docs/ja/DEPENDENCIES_GUIDELINES.md#1-信頼性popularity--ecosystem-trust)
+  - [セキュリティ](docs/ja/DEPENDENCIES_GUIDELINES.md#2-セキュリティsecurity--compliance)
+  - [コード品質](docs/ja/DEPENDENCIES_GUIDELINES.md#3-コード品質code-quality)
+  - [プロジェクト継続性](docs/ja/DEPENDENCIES_GUIDELINES.md#4-プロジェクト継続性project-sustainability)
+  - [ライセンス](docs/ja/DEPENDENCIES_GUIDELINES.md#5-ライセンスlicense-compliance)
+  - [選定プロセス](docs/ja/DEPENDENCIES_GUIDELINES.md#6-選定プロセスevaluation-process)
+  - [継続的チェック](docs/ja/DEPENDENCIES_GUIDELINES.md#7-継続的チェックongoing-review)
+  - [例外ルール](docs/ja/DEPENDENCIES_GUIDELINES.md#8-例外ルールexception-rules)
 
 ---
 
 ## 🏗️ 対象範囲
 
 このガイドラインには以下が含まれます：
+
 - コードレビューの責務と原則
 - プルリクエストのテンプレートとワークフロー
 - テストと証跡に関する必須要件
 - 効果的なコラボレーションのためのコミュニケーション心得
 
 ---
 
+## 📂 ディレクトリ構成
+
+```
+.
+├── docs/
+│   ├── en/               # 英語ドキュメント
+│   └── ja/               # 日本語ドキュメント
+├── LICENSE               # リポジトリのライセンス
+├── README.md             # 英語版 README
+└── README.ja.md          # このファイル (日本語版 README)
+```
+
+---
+
 ## 🤝 貢献について
 
 改善提案はいつでも歓迎します。  
-ただし、**レプスグループ 外部からのプルリクエストは受け付けていません**。  
+ただし、**レプスグループ 外部からのプルリクエストは受け付けていません**。
 
 詳細は [CONTRIBUTING.md](CONTRIBUTING.md) を参照してください。  
-社内メンバーは `main` ブランチに向けてプルリクエストを作成してください。  
+社内メンバーは `main` ブランチに向けてプルリクエストを作成してください。
 
 ---
 
@@ -54,4 +72,4 @@
 
 ---
 
-© レプスグループ – エンジニアリングチーム
+© レプスグループ – エンジニアリングチーム

README.md

@@ -1,50 +1,68 @@
 # LEPUS Development Guidelines ![version](https://img.shields.io/badge/version-1.0-blue)
 
+🇺🇸 **English** | 🇯🇵 [Japanese](README.ja.md)
+
 This repository contains the **development guidelines and best practices** of the Lepus Engineering Team.  
 It defines our principles for code review, pull requests, testing, and collaboration.
 
 ---
 
 ## 📖 Documentation Index
 
-- [Review Policy (日本語)](docs/ja/REVIEW_POLICY.md)
-  - [PR Size Guidelines (日本語)](docs/ja/REVIEW_POLICY.md#pr単位の原則)
-  - [Review Mindset (日本語)](docs/ja/REVIEW_POLICY.md#-レビューの心得)
-  - [簡易チェックリスト](docs/ja/REVIEW_POLICY.md#-簡易チェックリスト)
-  - [Level Decision Guide](docs/ja/REVIEW_POLICY.md#-レベル判定ガイド)
-  - [RACIマトリクス](docs/ja/REVIEW_POLICY.md#-raciマトリクス)
-- [Review Policy (English)](docs/en/REVIEW_POLICY.md)
-  - [PR Size Guidelines (English)](docs/en/REVIEW_POLICY.md#pr-size-guidelines)
-  - [Review Mindset (English)](docs/en/REVIEW_POLICY.md#-review-mindset)
+- [Review Policy](docs/en/REVIEW_POLICY.md)
+  - [PR Size Guidelines](docs/en/REVIEW_POLICY.md#pr-size-guidelines)
+  - [Review Mindset](docs/en/REVIEW_POLICY.md#-review-mindset)
   - [Quick Checklist](docs/en/REVIEW_POLICY.md#-quick-checklist)
   - [Level Decision Guide](docs/en/REVIEW_POLICY.md#-level-decision-guide)
   - [RACI Matrix](docs/en/REVIEW_POLICY.md#-raci-matrix)
-- [Pull Request Template (日本語)](docs/ja/PULL_REQUEST_TEMPLATE.md)
-  - [Test Evidence (日本語)](docs/ja/PULL_REQUEST_TEMPLATE.md#-テスト証跡)
-  - [Checklist (日本語)](docs/ja/PULL_REQUEST_TEMPLATE.md#-チェックリスト)
-- [Pull Request Template (English)](docs/en/PULL_REQUEST_TEMPLATE.md)
-  - [Test Evidence (English)](docs/en/PULL_REQUEST_TEMPLATE.md#-test-evidence)
-  - [Checklist (English)](docs/en/PULL_REQUEST_TEMPLATE.md#-checklist)
+- [Pull Request Template](docs/en/PULL_REQUEST_TEMPLATE.md)
+  - [Test Evidence](docs/en/PULL_REQUEST_TEMPLATE.md#-test-evidence)
+  - [Checklist](docs/en/PULL_REQUEST_TEMPLATE.md#-checklist)
+- [Third-Party Package Selection Guidelines](docs/en/DEPENDENCIES_GUIDELINES.md)
+  - [Objectives](docs/en/DEPENDENCIES_GUIDELINES.md#objectives)
+  - [Trustworthiness](docs/en/DEPENDENCIES_GUIDELINES.md#1-trustworthiness-popularity--ecosystem-trust)
+  - [Security & Compliance](docs/en/DEPENDENCIES_GUIDELINES.md#2-security--compliance)
+  - [Code Quality](docs/en/DEPENDENCIES_GUIDELINES.md#3-code-quality)
+  - [Project Sustainability](docs/en/DEPENDENCIES_GUIDELINES.md#4-project-sustainability)
+  - [License Compliance](docs/en/DEPENDENCIES_GUIDELINES.md#5-license-compliance)
+  - [Evaluation Process](docs/en/DEPENDENCIES_GUIDELINES.md#6-evaluation-process)
+  - [Ongoing Review](docs/en/DEPENDENCIES_GUIDELINES.md#7-ongoing-review)
+  - [Exception Rules](docs/en/DEPENDENCIES_GUIDELINES.md#8-exception-rules)
 
 ---
 
 ## 🏗️ Scope
 
 These guidelines cover:
+
 - Code review responsibilities and principles
 - Pull Request templates and workflows
 - Testing and evidence requirements
 - Communication mindset for effective collaboration
 
 ---
 
+## 📂 Directory Structure
+
+```
+.
+├── docs/
+│   ├── en/               # English documentation
+│   └── ja/               # Japanese documentation
+├── LICENSE               # Repository license
+├── README.md             # This file
+└── README.ja.md          # Japanese README
+```
+
+---
+
 ## 🤝 Contribution
 
 Suggestions for improvement are always welcome.  
-Please open a Pull Request against the `main` branch.  
+Please open a Pull Request against the `main` branch.
 
 ⚠️ **Note:** External contributions (PRs from outside the Lepus Group) are **not accepted**.  
-For details, see [CONTRIBUTING.md](CONTRIBUTING.md).  
+For details, see [CONTRIBUTING.md](CONTRIBUTING.md).
 
 ---
 
@@ -54,4 +72,4 @@ This repository is licensed under the [MIT License](LICENSE).
 
 ---
 
-© Lepus Group – Engineering Team
+© Lepus Group – Engineering Team