Tennis Live WebSocket (point-by-point)

WebSocket endpoint, not a plain GET: open it with an HTTP Upgrade to wss://api.citoapi.com/api/v1/tennis/live/ws. Push feed for live tennis. Requires an API key with tennis access AND the live-WebSocket add-on; without the add-on the upgrade is refused. Auth on the upgrade, any one of: x-api-key header, Authorization: Bearer, ?apiKey= or ?x-api-key= in the query string. On connect the server sends a self-describing {"type":"ready"} frame carrying the protocol and event list, so a client can discover the contract at runtime. Client frames: {"action":"subscribe","rooms":["match:{matchId}","all"]}, {"action":"unsubscribe","rooms":[...]}, {"action":"ping"}. Max 32 rooms per connection. Server frames: {"type":"subscribed"}, {"type":"pong"}, {"type":"error","code":"INVALID_JSON"|"BAD_ROOMS"}, and the events {"type":"POINT_UPDATE"} and {"type":"MATCH_FINISHED"}, each carrying a data object keyed by match_id. matchId values come from /tennis/matches/live. There is no SSE variant for tennis; the WebSocket is the only push transport.