Update changelog

CHANGELOG.md

@@ -5,6 +5,16 @@ All notable changes to this project 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
+
+### Added
+
+- Integrated a theme switcher into _Storybook_ to support toggling between the light and dark mode
+
+### Fixed
+
+- Fixed the _Storybook_ setup by resolving missing `@angular/material` styles
+
 ## 3.0.1 - 2026-04-26
 
 ### Changed