Stage333 Transparency Log Verification

1. Check execution session signature:
   gpg --verify docs/execution_session.json.sig docs/execution_session.json

2. Check transparency log hash chain locally:
   python3 core/verify_transparency_log.py

Meaning:
Stage333 records each signed execution session into an append-only transparency history.
Each entry contains the previous entry hash.
If any past entry is modified, the chain verification fails.