Changelog update.

CHANGELOG.md

@@ -13,6 +13,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ensures all function calls complete before returning results to the LLM (i.e.,
   before running a new inference with those results).
 
+- Added new Gradium services, `GradiumSTTService` and `GradiumTTSService`, for
+  speech-to-text and text-to-speech functionality using Gradium's API.
+
 ### Changed
 
 - Updated `AICFilter` to use Quail STT as the default model