fix: do not assume Python 3.14 has compression.zstd

[beer-psi]

Summary

It turns out the new compression.zstd module in 3.14 is optional.

References: aio-libs/aiohttp#11603 python/cpython#139707

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)

[emmatyping]

While it is optional, it should be available on pretty much every platform except custom builds on old old LTS Linux distros which are paid support only and WASI/Emscripten. If you don't want to support those platforms I'd argue you don't need to treat it as optional.

[beer-psi]

A library user was already affected by this due to aiohttp making the same assumption. zstd on Python is new and I wouldn't want to make the assumption that everyone has it when the PEP explicitly says "libzstd is optional".

#10327 (reply in thread)

[emmatyping]

Hm, gotcha, makes sense then!