Release v0.5.1

Fix Ruby 4.0 compatibility: add logger gem, fix AASM + Sequel
StateMachineStore key mismatch with anonymous classes.

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

Author: Matthieu Ciappara

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## [Unreleased]
 
+## [0.5.1] - 2026-03-27
+
 ### Fixed
 
 - Add `logger` gem to inline Gemfile for Ruby 4.0 compatibility (`logger` was removed from default gems).