contamination.py reads the repositories named by the held-out pilot manifest and by every
benchmark report (accepted_repos.json and NOTES.md links under benchmarks/measurements), marks
each run directory clean or contaminated with the report digest and time, and refuses to count
an unchecked run toward a gain. ablation.analyse carries excluded_from_gain when its run is
contaminated. Implemented by Codex (gpt-6-astra), gated here; the benchmark import is lazy so
the package imports without the benchmarks tree.
Co-Authored-By: Claude Fable 5.1 <[email protected]>
