…itional bulk association updates (#7581)

* Implement association operations in clause package with English comments (WIP)

- Add clause/association.go with AssociationOperation struct and related types
- Implement helper functions for creating association operations
- Add support for association operations in generics Set method
- Use English comments throughout the implementation
- Maintain compatibility with existing GORM functionality

* Add tests for clause.Association

- Add comprehensive tests for Association struct
- Test Assigner and AssociationAssigner interface implementations
- Test different association operation types
- Test AssociationAssignments method
- Ensure compatibility with existing clause package functionality

* Add integration tests for clause.Association

- Add comprehensive integration tests for clause.Association in generics API
- Test Association struct creation and interface implementations
- Test different association operation types
- Test AssociationAssignments method
- Ensure compatibility with existing generics functionality

* refactor code

* Add association generics test

* Add association tests

* Manual Code Review@1

* Manual Code Review@2

* Manual Code Review@3

* Manual Code Review@4

* Update

* generics: fix belongs-to Set(OpUpdate/OpDelete), refactor handler, add tests

* refactor code

* refactor code

* Add more association test cases

* refactor code

* Refactor code