List recently-moved events for the freshness sitemap

Open, top-level events whose odds moved in the trailing 24h.

A "mover" is an open, top-level event with at least one open market whose absolute 24h probability change (prob_24h_change, the same column the right-rail movers rail ranks on) clears min_abs_change. Ordered by the magnitude of the event's biggest market move so the most-newsworthy pages lead when the set exceeds limit; lastmod is the event's updated_at.

The main /sitemap/events carries the full open-event set with the same per-event lastmod; this endpoint is the concentrated subset a freshness <urlset> emits at higher priority to nudge a re-crawl of the pages that actually changed. The frontend handler caches at revalidate=3600, so this runs at most once per hour per worker.