chore: update CHANGELOG for #998

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

Author: brendan-kellam

CHANGELOG.md

@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Added generated OpenAPI documentation for the public search, repo, and file browsing API surface. [#996](https://github.com/sourcebot-dev/sourcebot/pull/996)
 
+### Fixed
+- [EE] Fixed account-driven permission sync silently wiping all Bitbucket Server repository permissions when the OAuth token expires on instances with anonymous access enabled. [#998](https://github.com/sourcebot-dev/sourcebot/pull/998)
+
 ## [4.15.5] - 2026-03-12
 
 ### Added