feat: support Optional[T] in Python

[crepererum]

I actually wanted to implement this but it turns out that Python 3.14 does this automatically for us (this doesn't "just work" in Python 3.13). Since we're using the release candidate for the not-yet-released 3.14, that's fine. I however decided to add a guard/check so nobody tries to run our WASM payload with an older version (or a too-new one).

[crepererum]

Here's why this works now:

Python 3.14.0rc2 (tags/v3.14.0rc2-dirty:31967d8, Aug 14 2025, 12:19:47) [Clang 18.1.2-wasi-sdk (https://github.com/llvm/llvm-project 26a1d6601d727a96f43 on wasi
Type "help", "copyright", "credits" or "license" for more information.
warning: can't use pyrepl: No module named 'termios'
>>> import typing
>>> import types
>>> x = typing.Optional[int]
>>> type(x)
<class 'typing.Union'>
>>> x.__args__
(<class 'int'>, <class 'NoneType'>)
>>>
>>> y = int | None
>>> type(y)
<class 'typing.Union'>
>>> y.__args__
(<class 'int'>, <class 'NoneType'>)

but this didn't used to work in older versions of Python:

Python 3.13.7 (main, Aug 15 2025, 12:34:02) [GCC 15.2.1 20250813] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import typing
>>> import types
>>> x = typing.Optional[int]
>>> type(x)
<class 'typing._UnionGenericAlias'>
>>> x.__args__
(<class 'int'>, <class 'NoneType'>)
>>>
>>> y = int | None
>>> type(y)
<class 'types.UnionType'>
>>> y.__args__
(<class 'int'>, <class 'NoneType'>)

so __args__ always worked, but the type was different. So I thought we needed some extra code, but no, Python just fixed that for us.