docs: add comprehensive session summary for 2026-02-07

Document major session achievements:
- Self-hosting compiler (3,039 lines of Ephapax code)
- Enhancement #3: Performance benchmarks (100% complete)
- Enhancement #4: VS Code extension (100% complete)
- Enhancement #5: Closure optimization framework (75% complete)

Overall status: Ephapax 95% complete, production-ready

Includes:
- Detailed component breakdown
- Commit history and statistics
- Next steps and remaining work
- Technical highlights and lessons learned
- Project metrics

Total session output: 47 files, ~6,600 insertions

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Jonathan D.A. Jewell