0.4.0

Added

• permessage-deflate (RFC 7692) wired end to end. The frame parser accepts RSV1 on the first frame of a data message when the compress parser option is on and delivers such messages as {compressed, text | binary, Payload}; ws_frame:encode_compressed/2 emits RSV1 frames. The session takes a deflate option (the negotiated parameters), inflates inbound messages bounded by max_message (a deflate bomb closes with 1009), validates text UTF-8 after inflating, and compresses outbound data frames with per-direction context takeover. ws_deflate:negotiate/2 and ws_deflate:parse_offer/1 negotiate straight from the raw Sec-WebSocket-Extensions elements.
• ws_client:connect/2 accepts compress => true to offer permessage-deflate and run the session compressed when the server agrees.
• ws_frame:valid_utf8/1: whole-payload UTF-8 check for consumers validating inflated text.

Changed

• The peer's close frame now reaches the handler: terminate/2 receives {remote, Code, Reason} when the peer's close carried a status code, and remote for a bare close.