add changelog entry

CHANGELOG.md

@@ -5,6 +5,16 @@ All notable changes to **Pipecat** will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Changed
+
+- Updated `AICFilter` to use Quail STT as the default model (`AICModelType.QUAIL_STT`). Quail STT is optimized for human-to-machine interaction (e.g., voice agents, speech-to-text) and operates at a native sample rate of 16 kHz with fixed enhancement parameters.
+
+### Deprecated
+
+- The `noise_gate_enable` parameter in `AICFilter` is deprecated and no longer has any effect. Noise gating is now handled automatically by the AIC VAD system. Use `AICFilter.create_vad_analyzer()` for VAD functionality instead.
+
 ## [0.0.96] - 2025-11-26 🦃 "Happy Thanksgiving!" 🦃
 
 ### Added