docs: add changelog entry for permission sync concurrency settings

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: brendan-kellam

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- Added `maxAccountPermissionSyncJobConcurrency` and `maxRepoPermissionSyncJobConcurrency` settings to configure concurrency for permission sync jobs (default: 8). [#840](https://github.com/sourcebot-dev/sourcebot/pull/840)
+
 ## [4.10.21] - 2026-02-02
 
 ### Added