Version 6.4.3

Bug fixes for the Java code generator and the structural metamodel API.

Bug Fixes

Java Generator: Self-Association Support (#441) - The Java generator now correctly handles self-associations (e.g., Employee manages Employee). - Previously, the Jinja2 template crashed because it identified association ends by type name, which fails when both ends point to the same class. - Self-associations now generate fields for both ends using role names, with proper getters, setters, and addTo methods. - Added test suite for the Java generator covering both normal and self-association scenarios.

DomainModel: Association Removal (#237) - Added DomainModel.remove_association(association) method that removes an association from the model and automatically cleans up references in all involved classes. - Previously, users had to manually call private _delete_association() on each class, which was error-prone and not documented.