Adjust for removal of typing.ByteString in Python 3.14

[michel-slm]

typing.ByteString has been removed:

https://docs.python.org/3.14/whatsnew/3.14.html

The modernizing guide suggests collections.abc.ByteString which has also been removed; the recommendation is to use either:

• just bytes
• collections.abc.Buffer
• a union of bytes, bytesarray, etc.

https://typing.readthedocs.io/en/latest/guides/modernizing.html#modernizing-byte-string

https://docs.python.org/3/library/collections.abc.html#collections.abc.ByteString suggests bytes | bytesarray so I'm going with that here.

[lyterk]

I think it's fine to just use bytes, it looks like the only caller using ByteString is struct.unpact, handling user input here. struct.unpack consumes bytes | bytesarray | memoryview. When handling user input from a string, only the bytes type make sense.

So we could easily just get rid of the ByteString type and use bytes with no loss of specificity or type safety.

[kellyjonbrazil]

So we could easily just get rid of the ByteString type and use bytes with no loss of specificity or type safety.

This is probably the way to go since the bytes | bytesarray syntax may not work for older Python versions, which we need to support:

https://github.com/kellyjonbrazil/jc/actions/runs/13249946013/job/36985283625?pr=639

[michel-slm]

I'll rework - should I start from the dev branch to make the PR cleaner?

[kellyjonbrazil]

Looks good - I'll merge when I start working on the next release. Thanks!