Changes to Per-country DATA FRESHNESS — when was each country last measured (max evidence.observed_at across OONI + CensoredPlanet + Voidly probes). Tells whether a high-risk/blocked verdict reflects live data or a stale months-old snapshot. Bands: live <=24h, recent <=7d, aging <=30d, stale >30d. ?country=XX filters to one.