v0.4.0

What's New

Video support

• negotiate_video_sdp — SDP answer for video media lines (H264, VP8, VP9, AV1)
• negotiate_av_sdp — combined audio+video negotiation in a single answer
• build_video_sdp — build video-only SDP offers for outgoing calls
• VideoCallSession — bridges video SDP negotiation to aiortp VideoRTPSession with frame callbacks
• SdpMessage.video and .video_rtp_address convenience properties

Improvements

• Extracted _BaseCallSession base class shared by CallSession and VideoCallSession
• Extracted _build_sdp_envelope helper to DRY SDP construction across 5 call sites
• Added GitHub Actions CI (tests on 3.11/3.12/3.13, ruff lint+format, mypy)

Fixes

• Removed dead _WELL_KNOWN_VIDEO_CODECS dict
• Removed unsafe aiortp.SUPPORTED_VIDEO_CODECS reference that could raise AttributeError
• Fixed pre-existing mypy no-redef error in uas.py
• Fixed license in README (BSD-3-Clause → MIT)