Replays a candidate INSTANT rule definition (it does not have to be saved) over a bounded window and reports what it would have matched. The headline figure is wouldNewlyDeclineCleanCount - accepted, non-fraud, non-chargeback transactions the rule would newly have pushed over the score border, i.e. its false positives. The result is an APPROXIMATE ClickHouse replay, not a re-run of the scoring engine; every response carries approximationNoteList explaining exactly why, and it must be surfaced rather than presented as an exact re-score. WINDOWED rules are rejected: replaying them needs a sliding per-dimension count over history and is not implemented. The window is capped at 30 days.