- Paymob gateway integration (auth→order→payment key→HMAC callback)
- Payment initiation endpoint with pending record + iframe URL
- Webhook callback with double-processing prevention
- Guardian absence reporting (excused status for future sessions)
- Contact messages (send + list with reply support)
- System settings migration seeding all mobile/payment config keys
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>