chore(release): prepare for 4.0.0-rc.6 (#889)

* chore(release): prepare for 4.0.0-rc.6

* chore(release): remove non-applicable changelog entry

Author: cosmir17

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to this project will be documented in this file.
 
 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).
 
+## [4.0.0-rc.6] - 2026-03-12
+
 ## [4.0.0-rc.5] - 2026-03-06
 
 ### 🐛 Bug Fixes