docs: mark v0.2.0 as released in CHANGELOG (#4)

Promote the Unreleased section to the v0.2.0 public release.

Author: mlwelles

CHANGELOG.md

@@ -3,7 +3,7 @@
 All notable changes to this project are documented here. The format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
-## [Unreleased]
+## [0.2.0] - 2026-07-08
 
 ### Added