chore(calendar-web): update changelog

Author: samuelreichert

packages/pluggableWidgets/calendar-web/CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased]
 
+### Fixed
+
+- Improved handling of the start date attribute to ensure correct calendar initialization.
+
 ## [2.3.0] - 2026-02-17
 
 ### Added