Apply latest Copier template updates

[AndrewSazonov]

This PR syncs the project with the latest Copier templates. Main changes include replacing deprecated Node.js 20 usage, migrating docstrings from Google style to NumPy style, and applying related template-driven configuration updates.

[henrikjacobsenfys]

I looked at a handful of randomly selected files, and they looked fine.

[rozyczko]

I spent way too much time on this PR :)

Rechecked actions version bump correctness,
Assured client-id is the new version of app-ad in create-github-app-token action
Checked dependency move in pyproject.toml
Got worried about manually copying trstringer/require-label-prefix action
Very useful addition of nodefaults to pixi channels
etc.

One potential issue I have is - do we really, REALLY, need to add the useless docstrings to all the methods?

def __init__(self):
    """Init function."""

def __call__(self, *args, **kwargs):
    """Call function."""

Instead of adding junk, why not just # noqa: DOC comment for those trivial dunder methods?