Make sure logging works with threads properly

[Jakuje]

SUMMARY

The libssh callbacks and log level is stored in thread-local variables so if we spawn threads in python, we need to make sure to reinitialize logging to make sure it works properely.

ISSUE TYPE

• Feature Idea

ADDITIONAL INFORMATION

Based on discussion in #597 which introduces the logging.

[webknjaz]

As a part of this, we'll need to

• produce free-threaded wheels (the ones marked with a t in the version component of the filename); this will improve our position in the wider Python ecosystem (https://hugovk.github.io/free-threaded-wheels/)
• start testing them (3.14t in CI)
• add a Trove classifier to the metadata

Testing in "nogil" runtimes is important because any races will be more evident in such envs.