Prepare release 5.3.0

Author: jensens

CHANGES.md

@@ -1,6 +1,11 @@
 ## Changes
 
-## 5.3.0 (unreleased)
+## 5.4.0 (unreleased)
+
+<!-- Add future changes here -->
+
+
+## 5.3.0 (2026-05-29)
 
 - Feature: The `uv` hook now also propagates `version-overrides` from `mx.ini` to `[tool.uv] override-dependencies` in `pyproject.toml`. This keeps version pins in sync between mxdev and uv-managed projects.
   [frapell]