`tarfile.open()` does not forward keyword arguments to the underlying `_Stream` object for zstd in stream mode

Bug report

Bug description:

I found the bug when I was browsing the source code, so I just put the source code here:

    @classmethod
    def open(cls, name=None, mode="r", fileobj=None, bufsize=RECORDSIZE, **kwargs):
        # irrevalent code...
        elif "|" in mode:
            # irrevalent code...
            compresslevel = kwargs.pop("compresslevel", 6)
            preset = kwargs.pop("preset", None)
            stream = _Stream(name, filemode, comptype, fileobj, bufsize,
                             compresslevel, preset)
            # irrevalent code...

But the doc says that:

For modes 'w:zst', 'x:zst' and 'w|zst', tarfile.open() accepts the keyword argument level to specify the compression level of the file. The keyword argument options may also be passed, providing advanced Zstandard compression parameters described by CompressionParameter. The keyword argument zstd_dict can be passed to provide a ZstdDict, a Zstandard dictionary used to improve compression of smaller amounts of data.

So there're three keyword arguments: level, options and zstd_dict that need to pass to _Stream constructor, and the constructor needs to change to accept these keyword arguments.

I'll open a PR to fix this soon.

CPython versions tested on:

3.14

Operating systems tested on:

No response

Linked PRs

• gh-139822

從 tarfile.open() 和 _Stream 建構函式開始，重點關注使用 zstd 的串流模式。驗證應如何轉送 level、options 和 zstd_dict，並確認對應的文件行為對 w|zst 有效；連結的 PR 表示這項工作已在進行中。