Merge WebSocket client functionality into HttpClient using Boost.Beast,
enabling a single client instance to handle both HTTP (libcurl) and
WebSocket (ws:// and wss://) protocols. Backward-compatible type aliases
(WebSocketClient, WebSocketClientBase) preserve existing code.
Changes:
- Add synchronous WebSocket client: ws_connect/ws_send/ws_recv/ws_close
- Support ws:// (plain TCP) and wss:// (TLS with SNI) connections
- Layered stream architecture with beast::tcp_stream for timeout support
- Binary message support via ws_send_binary()
- Update Makefile to link libcurl (-lcurl)
- Add README.md documenting unified HttpServer + HttpClient API
qing