Backtest Grid Radar's detectors over a past window

replay evaluates the current detectors every stepMinutes across [from, to) using only what was knowable at each step, through the same lifecycle the live store uses. recorded summarizes the episodes the store holds for the window, from the live evaluation and the history backfill. Both report per-detector occurrence counts, durations and peak severities alongside each episode, and every run is saved: list them with listInsightBacktests.