docs(changelog): note improved bucket error messages in admin API

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

Author: drernie

docs/CHANGELOG.md

@@ -16,6 +16,12 @@ Entries inside each section should be ordered by type:
 
 # Changelog
 
+## unreleased
+
+### Python API
+
+* [Fixed] `quilt3.admin.buckets.add/update/remove` now include the bucket name (and SNS ARN where applicable) in error messages, making failures easier to debug ([#4776](https://github.com/quiltdata/quilt/pull/4776))
+
 ## 7.2.0 - 2026-01-28
 
 ### Python API