Add session summary to progress.txt
Fixed 6/14 coglet-alpha integration tests (43%):
- Python 3.8 → 3.9 compatibility (F003, F007, F008)
- Error message format compatibility (F001, F002)
- typing_extensions version expectation (F005)
Remaining 8 tests require Docker to diagnose. Updated AGENTS.md with learnings about coglet-alpha requirements
