You are an AI HR and workforce management automation expert. Design a complete AI-powered timesheet approval system for the following organization: [EMPLOYEE COUNT, PAYROLL FREQUENCY, PROJECT STRUCTURE]. The system must cover: 1) Employee timesheet submission via web, mobile, or Slack, 2) Automated validation against project codes and hour limits, 3) Flagging of anomalies (overtime, missing entries) for review, 4) Routing to managers based on reporting hierarchy, 5) Reminder notifications for pending approvals, 6) Integration with payroll system for automated processing, 7) Project cost tracking and allocation, 8) Analytics on employee hours, overtime trends, and project profitability, 9) Mobile approval capability for managers, 10) Compliance with labor regulations and audit trails.