Make Monai (Random) Transforms work in a multi-threaded environment

With PEP 703 being accepted and implementation of it underway https://github.com/python/cpython/issues/108219 I think it would be great to prepare the Monai transforms early for execution on multiple threads. Especially with the large tensor sizes and the advantages of running transforms on GPU, I'm hoping for free-threading to have a big benefit in (3D) medical imaging AI.

I think the biggest issue here would be the Randomizable transforms, which currently can't be executed inside a threaded environment.

AFAIK, the free-threading is pushed by Meta, and I'm therefore expecting pytorch to be compatible with it relatively early, since one of the talks on no-gil python talked about testing it with a pytorch DL project internally at Meta.

This might be a great opportunity to work on https://github.com/Project-MONAI/MONAI/issues/6854 as well, which might eventually require breaking changes in the Randomizable API as well.

Start by reading MONAI's Randomizable transforms and the related issue #6854, then review the PEP 703 free-threading context linked here. The issue names no files or tests, so first establish the required thread-safety changes and whether the Randomizable API needs breaking changes. Done requires an agreed implementation that supports Randomizable transforms in a multi-threaded environment.