A hand-built proof binary and the published artifact share a version string
but not their bytes, so no version check could see the divergence. The agent
now reports agent_sha256 (hash of /proc/self/exe, once per process; empty =
unknown) beside agent_version, the same mechanism as host.wrapper_sha256.
The hub half (compare against the vouched agent_sha256, surface drift) is
owed in the hub repo.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS
