This PR improves the typehints for the missing attribute violation callback by specifying the exact callable signature.

Improved the lazy loading violation callback typehints, this change makes the callable signature more explicit by changing fromcallable|null to(callable(self, string))|null.

The callback receives:

• The model instance (self)
• The missing attribute key (string)

This provides better IDE support and makes the expected callback signature clearer to developers.