Sports prediction markets across Polymarket and Kalshi in one call — game lines, futures, and props (NFL/NBA/MLB/NHL/soccer/tennis/etc). Optionally narrow with league (a tag/category keyword, e.g. nfl, soccer, world-cup) and cap with limit. Each hit is tagged with its venue and returns the question, live YES/NO price (implied probability), USD volume, close date, and the venue URL. Read-only, keyless.