Function settle_poll 

pub async fn settle_poll(
    pool: &SqlitePool,
    url: &str,
    outcome: &PollOutcome,
    cadence: Duration,
)

Apply a PollOutcome to the feed’s row: settle the error columns AND reschedule it. Both halves, always, from one place.

The scheduler did this inline. web::add_subscription then copied only the first half, so a poll taken off the scheduler could clear a stale failure’s COUNT while leaving the feed parked on its stale backoff HORIZON — reported healthy, not polled for up to 24h. And its failures fed consecutive_errors with no reschedule, so repeated Subscribe clicks drove a shared feed to the 24h ceiling for every subscriber. Two copies of a sequence drift; this is the one copy.

cadence is the interval to use on success; the scheduler derives it from the feed’s hint, a direct caller passes the configured default. A store failure is logged and the reschedule still attempted, so a hiccup writing the count cannot strand the feed at a NULL next_poll that due_feeds would then re-poll every tick.