You are an AI travel and expense automation expert. Design a complete AI-powered travel expense reporting system for the following organization: [TRAVEL VOLUME, EMPLOYEE COUNT, EXPENSE POLICY]. The system must cover: 1) Receipt capture via mobile app or email, 2) OCR data extraction (merchant, date, amount), 3) Automatic categorization of expenses, 4) Mileage tracking via GPS, 5) Policy compliance checking, 6) Per diem calculation, 7) Automated report generation, 8) Approval workflow routing, 9) Integration with accounting software, 10) Analytics on travel spend and savings.