Make a clean clone reproducible without a sci-method checkout:
- vendor the frozen pre-registration (docs/prereg/, pinned SHA-256 f22331a7… unchanged)
and the 36-source bibliography into the repo
- confirmatory_run.py resolves the in-repo prereg first, falling back to the canonical
sci-method path; the SHA gate is identical (the pin, not the path, is the guarantee)
- add REPRODUCE.md: tiered clone→env→seed→run→analyze checklist, honest about the
isolated-engine containment rule and the 1.2 GB raw data that is not committed
Defensive-measurement instrument; no change to measured behavior.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>