Fix PyPy compatibility with super() calls in slotted dataclasses.

Apply closure cell repair mechanism to PyPy in addition to CPython.
The existing repair logic works correctly on PyPy since it uses
standard Python introspection APIs (__code__, __closure__, cell_contents).

Fixes TypeError: super(type, obj): obj must be an instance or subtype of type
when calling super() in methods of classes created with slots=True dataclass
transformations.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: emcd

sources/classcore/utilities.py

@@ -114,7 +114,7 @@ def qualify_class_name( cls: type ) -> str:
 def repair_class_reproduction( original: type, reproduction: type ) -> None:
     ''' Repairs a class reproduction, if necessary. '''
     match __.platform.python_implementation( ):
-        case 'CPython':  # pragma: no branch
+        case 'CPython' | 'PyPy':  # pragma: no branch
             _repair_cpython_class_closures( original, reproduction )
         case _: pass  # pragma: no cover