v0.2.1

Summary

• advance the package version to 0.2.1 after the failed v0.2.0 publish mismatch
• restore a clean release path where repo version, latest tag, and PyPI can agree
• keep script bootstrap and artifact smoke contracts green for wheel and sdist releases

Verification

• metadata_consistency.py against refs/tags/v0.2.1
• pytest tests/test_metadata_consistency.py -q
• python -m build
• release_contract_scan.py --artifact-dir dist
• twine check dist/.whl dist/.tar.gz
• release_smoke.py --artifact-dir dist --kind all
• install_release_extras.py --artifact-dir dist --extras pyg dgl
• release_smoke.py --artifact-dir dist --kind all --interop-backend all