Add setup.py / setup.cfg shim delegating sdist / bdist_wheel to maturin

[serge-wq]

Summary

Adds a minimal setup.py / setup.cfg shim so python setup.py sdist and python setup.py bdist_wheel delegate to maturin, for build environments that still drive distributions through setuptools instead of python -m build. Canonical build metadata remains in pyproject.toml / [tool.maturin].

Details

• setup.py: Custom sdist / bdist_wheel commands invoke maturin; if maturin is missing, the shim runs pip install maturin for the active interpreter (first-time installs may need network access).
• Version: 1.26.0.post0 in pyproject.toml and setup.cfg; temporalio.__version__ remains 1.26.0 unless aligned in a follow-up.
• Metadata: Project URLs updated to this fork’s GitHub location; documentation URL still points at the upstream project docs. Removed the License :: OSI Approved :: MIT License Trove classifier so setuptools ≥69 can merge pyproject.toml without a PEP 639 conflict (license remains MIT in [project]).
• .gitignore: *.egg-info/ for local setup.py / egg_info runs.

How to verify

git submodule update --init --recursive
export PATH="$HOME/.cargo/bin:$PATH"   # or your Rust install
python setup.py sdist
python setup.py bdist_wheel

[AdiLyft]

QQ, does anything in the build pipeline invoke setup.py sdist/bdist_wheel with --dist-dir?

The custom run() methods hardcode dist and ignore self.dist_dir, so the flag would be silently swallowed.

If yes, worth reading self.dist_dir instead:

dist_dir = getattr(self, "dist_dir", DIST_DIR)
self.mkpath(dist_dir)                                                                                                                                                                                                                                                      
_run_maturin(["sdist", "-o", dist_dir])

If nothing passes the flag, ignore this comment since default is "dist" and behavior is identical.