feat: Tuist 워크스페이스 전환 및 AtchaV2(메인 2.0) 모듈 기반 구축 - #338

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/