kn (DOM.РФ ЖК) is scheduled WEEKLY (settings.scrape_kn_cron='15 4 * * mon'),
but its freshness thresholds were fresh_days=2 / stale_days=5 — so the monitor
flagged kn "stale" every Wed-Sun by design, a guaranteed weekly false-positive
that would desensitize the team to the GlitchTip alert. The freshness monitor
(#1904) caught this on its first prod run (06-26 09:00 MSK: "kn [stale, 3.9d]").
Recalibrate to weekly cadence (mirror objective 7/14): fresh_days=8 (full week +
Monday-run completion buffer), stale_days=14 (alert only after ~two missed
Mondays). +regression test pinning kn stays fresh through the week.
Refs #73
