Build project with pyproject.toml and add pixi support

.gitattributes

@@ -1 +1,3 @@
 pymc/_version.py export-subst
+# SCM syntax highlighting & preventing 3-way merges
+pixi.lock merge=binary linguist-language=YAML linguist-generated=true

.gitignore

@@ -55,3 +55,6 @@ pixi.lock
 
 .jupyter/
 .claude/
+# pixi environments
+.pixi/*
+!.pixi/config.toml

pyproject.toml

@@ -1,7 +1,75 @@
 [build-system]
-requires = ["setuptools", "versioneer[toml]==0.29"]
+requires = ["setuptools>=77", "versioneer[toml]==0.29"]
 build-backend = "setuptools.build_meta"
 
+[project]
+name = "pymc"
+dynamic = ["version"]
+requires-python = ">=3.11,<3.14"
+authors = [{ name = "PyMC Developers", email = "[email protected]" }]
+description = "Probabilistic Programming in Python: Bayesian Modeling and Probabilistic Machine Learning with PyTensor"
+readme = "README.rst"
+license = "Apache-2.0"
+license-files = ["LICENSE"]
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Programming Language :: Python",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Intended Audience :: Science/Research",
+    "Topic :: Scientific/Engineering",
+    "Topic :: Scientific/Engineering :: Mathematics",
+    "Operating System :: OS Independent",
+]
+keywords = [
+    "statistics",
+    "modelling",
+    "inference",
+    "probabilistic-programming",
+    "bayesian-inference",
+    "science",
+]
+dependencies = [
+    "arviz>=0.13.0",
+    "cachetools>=4.2.1",
+    "cloudpickle",
+    "numpy>=1.25.0",
+    "pandas>=0.24.0",
+    "pytensor>=2.35.0,<2.36",
+    "rich>=13.7.1",
+    "scipy>=1.4.1",
+    "threadpoolctl>=3.1.0,<4.0.0",
+    "typing-extensions>=3.7.4",
+]
+
+[project.urls]
+repository = "http://github.com/pymc-devs/pymc"
+
+[project.optional-dependencies]
+tests = [
+    # "blas",
+    "jax",
+    "polyagamma",
+    # "python-graphviz",
+    "graphviz",
+    "networkx",
+    "zarr>=2.5.0,<3",
+    # Extra dependencies for testing
+    "ipython>=7.16",
+    "pre-commit>=2.8.0",
+    "pytest-cov>=2.5",
+    "pytest>=3.0",
+    "mypy==1.15.0",
+    "types-cachetools",
+    "numdifftools>=0.9.40",
+    # "mcbackend>=0.4.0",
+]
+
+[tool.setuptools.packages.find]
+include = ["pymc*"]
+
 [tool.pytest.ini_options]
 testpaths = ["tests"]
 minversion = "6.0"
@@ -101,3 +169,16 @@ exclude_lines = [
 
 [tool.coverage.run]
 omit = ["*examples*"]
+
+[tool.pixi.workspace]
+channels = ["conda-forge"]
+platforms = ["linux-64"]
+
+[tool.pixi.pypi-dependencies]
+pymc = { path = ".", editable = true }
+
+[tool.pixi.environments]
+default = { solve-group = "default" }
+tests = { features = ["tests"], solve-group = "default" }
+
+[tool.pixi.tasks]