Read the latest verifier backtest for a context lineage

Returns the most recent backtest run for the lineage’s current version and this org — its status and counters, the arrival split date, and every per-commit verdict ordered by commit date. The client groups the verdicts by verifier to render each verifier’s result inline.

One backtest covers all of the version’s verifiers, deduped on (org, version, source), so the latest run is the one the tab shows; there is no per-run id in the request. Responds with data: null when this org has never backtested the version.