chore(calendar-web): update changelog

Author: samuelreichert

packages/pluggableWidgets/calendar-web/CHANGELOG.md

@@ -16,6 +16,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 - We fixed an issue where the “On view range changed” event nanoflow did not trigger when switching from Day/Week to Month view, causing Month view to only load events from the last week instead of the full month range.
 
+- Updated the start date attribute logic to use EditableValue and handle null cases correctly, preventing errors when the attribute is unset or missing.
+
 ## [2.2.0] - 2025-11-11
 
 ### Added