refactor: 공통으로 사용하는 도메인 모델을 common 패키지로 추출 #68

All 102 tests pass in 35s

102 tests +102 102 ✅ +102 35s ⏱️ +35s
67 suites + 67 0 💤 ± 0
67 files + 67 0 ❌ ± 0

Results for commit c3cd66e. ± Comparison against earlier commit 12ac8c1.