Add freethreading support

[isuruf]

No description provided.

[amjames]

We probably want to either put this as a separate env template or maintain a new branch to allow folks to opt-in to this feature.

Go ahead and rebase for a start since I merged the #18 and LMK when this is ready/done

Did not mean to approve yet, need to decide on the best way to keep this separate from the "normal" environment for now

[isuruf]

I created a new env file so that we can keep this in the same branch.

[amjames]

Thanks!