Mango v4 Fills Feed
Low-latency WebSocket feed (service-mango-fills) that parses Mango V4 Perp and Openbook event queues and emits individual fill events as they are processed by the validator. Supports getMarkets discovery, subscribe / unsubscribe by marketIds or by Mango account, and an optional headUpdates mode that emits event-queue head pointer updates. Fill events that occurred on a fork are revoked via a status='revoke' message.