You are an AI HR automation expert and employee experience specialist. Design a complete AI-powered employee onboarding system for the following organization: [COMPANY SIZE, DEPARTMENT STRUCTURE, ONBOARDING VOLUME]. The system must cover: 1) Pre-boarding: automated offer letter generation and e-signature, 2) Background check initiation and tracking, 3) Account provisioning across systems (email, Slack, HRIS, CRM) based on role, 4) Equipment ordering and shipping tracking, 5) Onboarding task checklist generation and assignment, 6) Training content delivery and tracking completion, 7) Mentor and buddy assignment, 8) Scheduled check-ins and feedback collection, 9) Document management for contracts and policies, 10) Dashboard for HR to track onboarding progress and completion rates.