Mint-backed WebSocket transport for the connection socket.
Defaults the WebSocket HTTP transport to HTTP/1.1 so the WhatsApp socket matches Baileys' ws client behavior instead of attempting Mint's HTTP/2 extended CONNECT path.
ws
@type phase() :: :upgrade_pending | :open
@type t() :: %BaileysEx.Connection.Transport.MintWebSocket{ adapter: module(), conn: term(), phase: phase(), request_ref: term(), response_headers: list(), status: non_neg_integer() | nil, websocket: term() | nil }