Use this skill for CallKit and PushKit VoIP implementation and review across CXProviderConfiguration, CXProvider, CXCallController, CXCallUpdate, incoming and outgoing calls, provider delegates, answer/end/mute/hold actions, VoIP push token and push handling, audio-session coordination, and Call Directory extensions. Do not use for generic notifications, AVKit playback, ordinary audio sessions, or app architecture without CallKit lifecycle work.
