Markets WebSocket — stream real-time market price updates

Establishes a WebSocket connection for streaming V2 market price changes in real-time.

Connection: wss://therundown.io/api/v2/ws/markets?key=YOUR_API_KEY

Filter parameters (query string):

• affiliate_ids — comma-separated affiliate IDs
• sport_ids — comma-separated sport IDs
• event_ids — comma-separated event IDs
• market_ids — comma-separated market IDs

All filters are optional. If none are specified, all messages are received.

Heartbeat: Server sends {"meta":{"type":"heartbeat"},"data":{"now":"<RFC3339>"}} every 15 seconds.

Message format:

{
  "meta": {...},
  "data": {
    "affiliate_id": 19,
    "sport_id": 4,
    "event_id": "abc123",
    "market_id": 1,
    ...
  }
}

Queue: 256-message buffer per client. If the client falls behind, messages are dropped.