Move build system to meson-python

[ndgrigorian]

This PR proposes moving from setuptools to meson-python as the mkl-service build system

meson-python is already used by NumPy and allows setup.py to be removed (with its logic moved into the meson.build script)

Also adds mkl as a dependency

[Copilot]

Pull request overview

This PR migrates mkl-service from a setuptools/setup.py-driven build to a meson-python build, updating conda recipes and CI workflows accordingly, and adding an mkl runtime dependency.

Changes:

• Remove setup.py and define extension builds/install layout in meson.build (C + Cython extensions, Python sources, tests).
• Switch pyproject.toml build backend to mesonpy and add mkl to runtime dependencies.
• Update conda recipes and GitHub Actions workflows to build/install via pip/python -m build instead of setup.py.

Reviewed changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
setup.py	Removed legacy setuptools build script.
pyproject.toml	Switched build backend to mesonpy, updated build requirements and runtime deps.
meson.build	Added Meson build definition for C/Cython extensions and installation layout.
mkl/_py_mkl_service.pyx	Added/introduced Cython wrapper implementation used by the public API.
conda-recipe/meta.yaml	Updated conda build requirements for Meson-based builds.
conda-recipe/build.sh	Updated wheel build/install flow (no setup.py).
conda-recipe/bld.bat	Removed setup.py clean step and MKLROOT usage.
conda-recipe-cf/meta.yaml	Updated conda-forge recipe host requirements for Meson-based builds.
conda-recipe-cf/build.sh	Switched to pip install . build/install flow.
conda-recipe-cf/bld.bat	Switched to pip install . build/install flow.
.github/workflows/build-with-standard-clang.yml	New CI job building with system clang.
.github/workflows/build-with-clang.yml	Updated IntelLLVM clang CI job to Meson-based install.
.github/workflows/build_pip.yml	New CI job testing editable install + (pre-)release NumPy in conda env.

[Copilot]

run_command('python', ...) hardcodes the interpreter, which may not match Meson’s discovered Python (virtualenv/pyenv/Windows). Use the py installation found by import('python').find_installation() when computing the version to avoid mismatched interpreters.

Suggested change

	'python', '-c',
	import('python').find_installation(pure: false), '-c',

[Copilot]

The matrix value numpy_version: ["numpy'>=2'"] includes embedded quotes and will be passed verbatim to pip install, which is not a valid requirement specifier. Use something like numpy>=2 (or just install numpy and control pre-releases separately).

Suggested change

	numpy_version: ["numpy'>=2'"]
	numpy_version: ["numpy>=2"]

[Copilot]

The matrix value numpy_version: ["numpy'>=2'"] includes embedded quotes and will be passed verbatim to pip install, which is not a valid requirement specifier. Use something like numpy>=2.

Suggested change

	numpy_version: ["numpy'>=2'"]
	numpy_version: ["numpy>=2"]