Add free threaded Python 3.14t to the testing

[cclauss]

https://www.python.org/downloads/release/python-3140/

• Continues the work of Add Python 3.14 to the testing #355

[ddelange]

what's the use-case here, since this package does nothing free-threading related?

[cclauss]

https://github.com/search?q=repo%3Aahupp%2Fpython-magic%20threading is light use of the threading, but that might change over time, and it is better to have guardrails 🚧 in place than drive off the mountain ⛰️ .

If you want, we can close.

[ddelange]

no all good! just curious 👍

[ddelange]

see commit description: 8a35137

might make sense to add a small test in this PR?

[ddelange]

could argue there should be a global variable LOCK = threading.Lock(), which is used as lock keyword argument default value in the global scope from_buffer, from_file, from_descriptor functions, because those are the functions that are not thread-safe to begin with

[cclauss]

Cool! Let's do this. I will close this PR with unmerged commits. Please recreate it and add the tests that you envision.