Reduce noise in future script modifications

Reduce git diffs in future code modifications

Since 2023 pyproject.toml is the only used mechanism for building
python packages in ITK.

Update documentation to only include valid python versions.

Building python packages with 3.26.6 allows for support of Development.SABIModule
capabilities.

…-whitespace

strip trailing whitespace

Fail early if the version is incompatible with PEP 440.

…tation-cleanups

script documentation cleanups

Add pre-commit hooks in Utilities/Hooks/ matching ITK's directory
structure and commit message enforcement:

- prepare-commit-msg: Inserts ITK prefix instructions into the commit
  message editor so developers see valid prefixes while composing.

- kw-commit-msg.py: Validates commit messages with the same rules as
  upstream ITK: prefix check (BUG/COMP/DOC/ENH/PERF/STYLE/WIP),
  subject line max 78 chars, no leading/trailing whitespace, empty
  second line, and Merge/Revert exemptions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

…mmit-conventions

ENH: Add pre-commit hook to enforce ITK commit message conventions

…n 3.10+

scikit-ci-addons' install-python.ps1 downloads get-pip.py from a pinned
GitHub gist (jcfr commit 8478d43e) rather than the canonical
bootstrap.pypa.io URL, and installs a pip old enough to vendor an
html5lib that still uses `from collections import Mapping`.  That
import was removed in Python 3.10, so the very first invocation of
`python -m pip install pip --upgrade` (the bootstrap step in
`build_wheels`) dies with:

    File ".../pip.zip/pip/_vendor/html5lib/_trie/_base.py", line 3
    ImportError: cannot import name 'Mapping' from 'collections'

The failure is consistent on Python 3.10 and 3.11 across all Windows
matrix jobs (build-windows-python-packages (10) and (11)).

Fix it by running `python -m ensurepip --upgrade --default-pip` BEFORE
the existing `pip install pip --upgrade`.  ensurepip uses the pip wheel
that CPython itself bundled at release time (>= 21.x for Python 3.10),
which has a working html5lib >= 1.1, and the subsequent self-upgrade
then proceeds normally.

The PowerShell entry point (windows-download-cache-and-build-module-wheels.ps1)
still IEXes the upstream install-python.ps1 unchanged - the chicken-and-egg
fix is purely Python-side, so no interaction with scikit-ci-addons is
required.  Companion `windows_build_wheels.py` is unchanged because its
pip operations go through a virtualenv created by `virtualenv.exe`, and
modern virtualenv ships its own bundled pip wheels rather than copying
the (broken) system pip.

Surfaced by KitwareMedical/ITKUltrasound#246, which is the first remote
module PR to actually exercise the python wheel build matrix on Python
3.10+ after a related CI fix made the workflow start running again.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

…tions-mapping

COMP: Bootstrap pip via ensurepip on Windows wheel build to fix Python 3.10+