* Migrate from `typing_extensions` to `typing` for supported Python versions, and update code to use modern type hinting with unions and annotations. * Update type hinting to use lowercase generics for Python 3.9+ compatibility.
* Migrate from `typing_extensions` to `typing` for supported Python versions, and update code to use modern type hinting with unions and annotations. * Update type hinting to use lowercase generics for Python 3.9+ compatibility.