Not respecting closed stdin

[iakremnev]

When Python process is launched with a closed stdin descriptor, sys.stdin object is initialized as regular instead of being set to None.

For demonstration purpose, ghcr.io/astral-sh/uv:debian Docker image is used.

$ uv run --managed-python python -c 'import sys; print(sys.stdin)' <&-
<_io.TextIOWrapper name='<stdin>' mode='r' encoding='utf-8'>
$ /usr/bin/python3 -c  'import sys; print(sys.stdin)' <&-
None

Ideally this behavior should be consistent with reference CPython implementation.

Oddly enough, using --no-managed-python with uv run also produces TextIOWrapper object. As well as running the installed Python directly without invoking uv.