A finished 12-minute humaneval bench died at the save line: some scorer
detail carried a non-JSON object (Ellipsis) and report.save's json.dumps
had no default. Every dumps on the save path now stringifies exotic
objects instead of killing the run; verified by replaying the exact
crashed checkpoint end-to-end (pass 82.3%, 15s, no crash).
Co-Authored-By: Claude <noreply@anthropic.com>