v0.7.0a4

What's Changed

• docs: update changelog for v0.7.0a4 release
• Fix mypy: import pcm16_to_mulaw from _mulaw instead of fastrtc
• Replace audioop with pure-Python G.711 mu-law codec
• Fix CI: suppress audioop DeprecationWarning on Python 3.12
• Fix SIP backend: port leak on start failure, close-before-cleanup race
• docs: add changelog and guide for configurable SIP jitter buffer
• Fix CI: mypy errors, coverage threshold, and SIP dial test failures
• docs: add changelog entries for v0.7.0a2, a3, and a4
• Fix TwilioWebSocketBackend disconnect wiring and cleanup stale state
• docs: add SIP + ElevenLabs Conversational AI example
• Use stateful soxr stream resampler in TwilioWebSocketBackend
• Fix TwilioWebSocketBackend: feed native 8kHz to pipeline
• Fix WavFileRecorder silence gaps and add tests
• Add TwilioWebSocketBackend and RecordingChannelMode.ALL

Full Changelog: v0.7.0a3...v0.7.0a4