Withing 1. Features 채팅 친구 초대 기능 (이메일 발송 ?) 연락처 동기화 (Card Dav) 2. App Architecture 2-1. 모듈 2-1-1. App Core Presentation Data Domain 3. Library DI Hilt Network Retrofit Logger Database Server Design Material 3 CI / CD Jenkins with Firebase Test 4. Conventions