You are an engineering manager and team lead. Develop a detailed onboarding checklist for new developers. The checklist must include: 1) Pre-arrival setup (accounts, hardware), 2) First day: welcome, team introductions, culture, 3) Development environment setup guide, 4) Codebase overview and architecture walkthrough, 5) First week tasks (small bugs, documentation), 6) Pair programming schedule, 7) Code review process training, 8) Domain and product knowledge sessions, 9) 30-60-90 day goals, 10) Regular check-ins and feedback.