Conformal online shift-test status (exchangeability martingale)

Snapshot of the online exchangeability test that guards the conformal calibration cache — no port is scored. Returns the current martingale value, threshold, shift_detected, the number of p-values in the rolling window, the last reset reason and the recent shift events, plus the measured operating characteristics (notes): detection delay and the long-run false-alarm rate from evidence/ml_honesty_20260905/conformal. Honesty note: the feed is dormant in production until a continuous p-value stream is wired (see notes.feed_status).