docs: Add comprehensive session summary for 2025-01-14

Complete overview of Phase 2 async architecture design, Symfony Messenger
research, Phase 0 profiling setup, and lessons learned from PR #55.

Highlights:
- TYPO3 v13 Symfony Messenger integration research complete
- Phase 2 architecture revised to use built-in message queue
- Consensus validation by 3 AI models
- Xdebug profiling in progress to validate database bottleneck
- Clean branch created from main (not failed PR #55)

Next: Complete profiling analysis and begin Phase 1 implementation

Author: CybotTM