Toshiki Kataoka

I'll try to split the fix for #4486 into a smaller PR.

> I'll try to split the fix for #4486 into a smaller PR. Done. #5964

/test mini

I should not ban `cupy.sum(x, axis=[0])` in this PR with label `cat:code-fix`. FYI, ```python x = [1, 2, 3] numpy.sum(x, axis=[0])) # => TypeError("'list' object cannot be interpreted as an...

- Maybe `python_scalar_on_gpu` is a clearer name. - The policy on reduction functions could be generalized for the Python scalar cases. https://docs.cupy.dev/en/latest/reference/difference.html#zero-dimensional-array

For example, the install location of (nb or lab) extensions (`[tool.hatch.build.targets.wheel.shared-data]`) seems better to use JavaScript name, i.e. ```diff -"{{ cookiecutter.python_package_name }}/labextension" = "share/jupyter/labextensions/{{ cookiecutter.python_package_name }}" +"{{ cookiecutter.python_package_name }}/labextension" =...