fix(audio): address CoreML VAD review feedback

crates/chanora_audio/src/vad/mod.rs

@@ -1,9 +1,9 @@
 //! Voice activity detection backends and helpers.
 //!
-//! iOS capture feeds VoiceProcessingIO-processed microphone frames into
-//! this module and uses the realtime-safe WebRTC fallback. Other
-//! platforms may use a model-backed detector when available so
-//! VoiceActivity mode never collapses back to Continuous transmit.
+//! Apple capture feeds VoiceProcessingIO/CoreAudio-processed microphone
+//! frames into this module and prefers Apple CoreML Silero VAD when the
+//! Swift bridge is linked. WebRTC VAD remains the realtime-safe fallback;
+//! non-Apple platforms may use ONNX-backed Silero when available.
 
 #[cfg(any(target_os = "ios", target_os = "macos"))]
 pub mod apple_coreml;