[Feat] Support Python 3.14

[echoix]

Is your feature request related to a problem? Please describe.
Python 3.14 is the next version of Python. Python 3.14rc1 is now available to try out.

The official release of 3.14.0 is scheduled for Tuesday, 2025-10-07

There will be no ABI changes from this point forward in the 3.14 series, and the goal is that there will be as few code changes as possible.

##Call to action
We strongly encourage maintainers of third-party Python projects to prepare their projects for 3.14 during this phase, and where necessary publish Python 3.14 wheels on PyPI to be ready for the final release of 3.14.0, and to help other projects do their own testing. Any binary wheels built against Python 3.14.0rc1 will work with future versions of Python 3.14. As always, report any issues to the Python bug tracker.

https://www.python.org/downloads/release/python-3140rc1/

Describe the solution you'd like
Start testing our project with 3.14 in CI

Describe alternatives you've considered
Get affected with all issues of 3.14 at once on release.

Additional context
3.13 support is still not done in CI after a year.

3.14 has some changes that will probably need adjusting on Linux, but this adjustments would be the same as needed to make that "bad" code work on Windows or Linux. (Referring to Multiprocessing start method https://docs.python.org/3.14/whatsnew/3.14.html#incompatible-changes, https://docs.python.org/3.14/whatsnew/3.14.html#whatsnew314-concurrent-futures-start-method https://docs.python.org/3.14/whatsnew/3.14.html#whatsnew314-multiprocessing-start-method)