`zipfile.ZipFile.writestr()` raises `AttributeError` instead of accepting `os.PathLike` objects (e.g. `pathlib.Path`)

Bug report

Bug description:

Unlike ZipFile.write() (which accepts os.PathLike objects such as pathlib.Path for both its filename and arcname arguments), ZipFile.writestr() fails when passed a PathLike object as its zinfo_or_arcname parameter.

Instead of converting it to a string using os.fspath() (as expected by modern standard library conventions), it attempts to call .find(chr(0)) directly on the path object, resulting in an immediate AttributeError.

Repro:

import zipfile
import pathlib
import io
z = zipfile.ZipFile(io.BytesIO(), 'w')
# Passes a pathlib.Path instead of a raw string
z.writestr(pathlib.Path('foo.txt'), b'hello')

Traceback:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../zipfile/__init__.py", line 2020, in writestr
    zinfo = ZipInfo(zinfo_or_arcname)._for_archive(self)
            ^^^^^^^^^^^^^^^^^^^^^^^^^
  File ".../zipfile/__init__.py", line 455, in __init__
    filename = _sanitize_filename(filename)
  File ".../zipfile/__init__.py", line 410, in _sanitize_filename
    null_byte = filename.find(chr(0))
                ^^^^^^^^^^^^^
AttributeError: 'PosixPath' object has no attribute 'find'

CPython versions tested on:

3.14

Operating systems tested on:

macOS

Start in zipfile/init.py at ZipFile.writestr(), ZipInfo.init(), and _sanitize_filename(), then run the pathlib.Path reproduction from the issue. Done means writestr() accepts os.PathLike objects such as pathlib.Path without raising AttributeError while retaining existing string behavior.