Detailed implementation plan with 9 phases: 1. Database models and migrations 2. Cryptography and FIEL services 3. SAT communication services 4. CFDI XML parser 5. Main orchestrator service 6. Scheduled cron job 7. API endpoints 8. Frontend components 9. Testing and validation Includes: - 16 new files to create - 5 files to modify - Dependencies list - Implementation order Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>