Support free-thread build

[TingDaoK]

Issue #, if available:

• Original: Build Python 3.14 free-threaded wheels. #722

Description of changes:

• https://docs.python.org/3/howto/free-threading-extensions.html
• [PyList_GetItem](https://docs.python.org/3/c-api/list.html#c.PyList_GetItem) is not thread safe with free-threading, it should be fine in our code, since we just take the passed in list. But, it's just one time check and use, using strong ref should not add any overhead
• Free-thread uncovers a race condition in aio/http.py, which we are not locking the queue from native thread vs the eventloop.

TODO:

• Prebuild wheel for 13t and 14t

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.