After the clock steps back (dual-boot RTC in local time, NTP correction,
a state dir copied from a skewed machine) the future copy sorts last, so
the gate saw it as not recent and every 2s flush made a new copy,
pruning the older 15-minute history within minutes. Judge recency by the
newest copy that is not in the future.

Co-authored-by: Grok Bot <grok-bot@users.noreply.github.com>