Size-the-room for a Hyperliquid market. POST {coin, n?}. Returns the top N (default 10, max 25) traders on a coin ranked by volume, each with skill_score + classification + liquidation_count. Pre-trade check for MM agents: 'who am I about to be against on this perp, and have they been liquidated before?' Coin format: BTC, @107 (spot), xyz:SILVER.