docs(changelog): add auth API entry

Author: KonradStanski

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Added documentation for public API authentication in the generated OpenAPI spec and docs. [#101](https://github.com/sourcebot-dev/sourcebot/issues/101)
 
 ## [4.16.2] - 2026-03-25