docs: add changelog entries for data export bug fixes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: samuelreichert

packages/pluggableWidgets/datagrid-web/CHANGELOG.md

@@ -6,6 +6,16 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased]
 
+### Fixed
+
+- We fixed an issue where custom content columns ignored the export type setting, causing numbers and dates to always export as text in Excel.
+
+- We fixed an issue where exported date values included a hidden time component even when the format specified date-only parts.
+
+- We fixed an issue where boolean values exported as TRUE/FALSE instead of Yes/No to match the display in the grid.
+
+- We fixed an issue where numbers with more than 15 significant digits lost precision during Excel export. Such values are now exported as text to preserve all digits.
+
 ## [3.9.0] - 2026-03-23
 
 ### Changed