Add support for free threaded python

[ntjohnson1]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
Free threaded python is being explored https://docs.python.org/3/howto/free-threading-python.html
Right now the infrastructure isn't fully built out but is continuing to expand and many major packages are starting to add support (sometimes marked experimental)

Describe the solution you'd like
It would be nice to understand the scope of work required to support free threading.
Skimming the pyo3 description it looks like the previous work to mark all/most classes as frozen should make the transition easier. However, there is still the infrastructure burden because free threading requires a separate wheel for each python version (3.13 and 3.14 currently). https://pyo3.rs/v0.27.2/free-threading

Additional context
Linking issue from Rerun which motivated starting to look into this rerun-io/rerun#12269