Added support for Cryptex (RFC 9335)

This is final part of Cryptex (RFC 9335) implementation for pion/webrtc.
Public API is based on WebRTC Extensions specification (W3C Editor's
Draft from 19 December 2025).

Author: sirzooro

configuration.go

@@ -52,4 +52,8 @@ type Configuration struct {
 	// SDPSemantics controls the type of SDP offers accepted by and
 	// SDP answers generated by the PeerConnection.
 	SDPSemantics SDPSemantics `json:"sdpSemantics,omitempty"`
+
+	// RtpHeaderEncryptionPolicy affects whether RTP header extension encryption
+	// (RFC 9335 Cryptex) is negotiated.
+	RtpHeaderEncryptionPolicy RtpHeaderEncryptionPolicy `json:"rtpHeaderEncryptionPolicy,omitempty"`
 }

configuration_js.go

@@ -37,5 +37,9 @@ type Configuration struct {
 	// ICECandidatePoolSize describes the size of the prefetched ICE pool.
 	ICECandidatePoolSize uint8
 
+	// RtpHeaderEncryptionPolicy affects whether RTP header extension encryption
+	// (RFC 9335 Cryptex) is negotiated.
+	RtpHeaderEncryptionPolicy RtpHeaderEncryptionPolicy
+
 	Certificates []Certificate `json:"certificates,omitempty"`
 }