docs: add changelog entry for #1620

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VsjLedntEDA6nHFmfYYHAQ

Author: claude

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- Added a notes column to the nightly CVE remediation run summary that the agent can write per-issue outcome notes into. [#1620](https://github.com/sourcebot-dev/sourcebot/pull/1620)
+
 ## [5.1.10] - 2026-08-27
 
 ### Fixed