add license explanation

README.md

@@ -16,6 +16,32 @@ It enables dynamic content creation and management through a modular architectur
 
 Detailed information on how to use and extend CondationCMS can be found in the official [documentation](https://condation.com/documentation).
 
+## CondationCMS – Module & Extension Exception (Developer FAQ)
+
+In short:
+
+You may develop modules and extensions for CondationCMS under any license, including proprietary or commercial licenses.
+
+The only requirement: your module or extension must interact exclusively through the official Module/Extension API.
+
+You cannot copy or modify CondationCMS core code if you want your module/extension to remain proprietary.
+
+Modules and extensions must be installable and removable without altering core files.
+
+Any modifications to the core itself remain under the GPL.
+
+Examples:
+
+A module adding new functionality → can be closed-source or commercial.
+
+An extension visualizing CMS data → can be sold commercially.
+
+Modifying core classes (CoreEngine, ManagerUI) → GPL applies, even if a module is built alongside.
+
+Developer shortcut:
+
+“Anything that runs through the API can use your license. Anything touching the core stays GPL.”
+
 ## Changelog
 
 [Changelog](CHANGELOG.md).