Implement sjnetpkg 0.1.0, a Git-based package manager

Packages are ordinary Git repositories carrying a sjnetpkg.toml, so sjnetpkg
only needs to resolve, clone, track and run them instead of inventing an
archive format or build system. This adds the v0.1 CLI (install from registry
or Git URL, remove, list/inspect, registry update, run) on top of the Python
standard library, together with a test suite.

🤖 Generated with Codebuff
Co-Authored-By: Codebuff <noreply@codebuff.com>

pyproject.toml

@@ -0,0 +1,23 @@
+[build-system]
+requires = ["setuptools>=68"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "sjnetpkg"
+version = "0.1.0"
+description = "A simple Git-based package manager."
+readme = "README.md"
+requires-python = ">=3.11"
+dependencies = []
+
+[project.scripts]
+sjnetpkg = "sjnetpkg.cli:main"
+
+[project.optional-dependencies]
+test = ["pytest>=7"]
+
+[tool.setuptools.packages.find]
+where = ["src"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]