Python formatting: replace Black with Ruff

[agarny]

Fixes #542.

[Copilot]

Pull request overview

Replaces Black with Ruff as the Python formatter across build configuration, CI, and CMake targets.

Changes:

• Swap [tool.black] for [tool.ruff] in pyproject.toml (excluding extern).
• Replace BLACK_EXE discovery and PYTHON_FORMATTING_AVAILABLE gating with RUFF_EXE in CMake.
• Update CI workflow to install and invoke Ruff instead of Black; bump patch version.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
VERSION.txt	Patch version bump.
pyproject.toml	Replaces Black config with Ruff config.
cmake/formatting/CMakeLists.txt	Calls ruff format for check/format targets.
cmake/environmentchecks.cmake	Finds and advertises RUFF_EXE in lieu of BLACK_EXE.
.github/workflows/ci.yml	Installs Ruff instead of Black in the formatting job.

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