[no-ci] Prepare cuda.core v1.2.2 with Python 3.15 support

[Andy-Jost]

On hold: [no-ci] stays in the title until cuda-bindings 12.9.10 has cp315 wheels on PyPI. The CUDA 12 Python 3.15 jobs install that release, so they cannot pass before then. Then the prefix comes off, CI runs, and this merges.

Summary

Patch release of cuda.core 1.2.1 that adds Python 3.15 wheels, including the free-threaded build. Python 3.10 stays supported, so #3080 (which also drops 3.10) cannot be cherry-picked; this PR takes only its 3.15 parts plus the matching 13.4.4 release changes. The cuda-python 13.4.4 metapackage ships 3.15 support and pins cuda-core~=1.2.0, so pip install cuda-python on Python 3.15 needs a 1.2.x release with cp315 wheels. PyPI rejects new files for a release after 14 days, so the wheels cannot be added to 1.2.1. Part of #2163.

Changes:

• Cherry-pick ci: bump cibuildwheel to v4.2.1 and drop cpython-prerelease enable #2898: cibuildwheel v4.1.1 -> v4.2.1 and drop CIBW_ENABLE: cpython-prerelease. v4.1.1 predates CPython 3.15.0rc1, so the cp315 wheels this branch built for 1.2.1 used a beta interpreter with no ABI guarantee. v4.2.1 builds 3.15 by default against 3.15.0rc2, which is ABI-compatible with the final release. The one conflict was the cibuildwheel pin.
• Port the workflow parts of Prepare the 13.4.4 release #3096 (the 13.4.4 release): ci/tools/download-wheels no longer skips Python 3.15 artifacts, and the allow-prereleases and Windows continue-on-error guards for 3.15 go away. The Linux continue-on-error guard goes too, so 3.15 test failures fail CI.
• ci/test-matrix.yml: add Python 3.15 test jobs on CUDA 12.9.1 and 13.4.2 (linux-64 3.15 and 3.15t, win-64 3.15). Like every other job on this branch, they test against published cuda-bindings, here 12.9.10 and 13.4.4, the first releases with cp315 wheels and the ones users get on Python 3.15. For these test versions env-vars would pick CI-built bindings, so each 3.15 row sets BINDINGS_SOURCE=published and the two skip flags through its ENV map, the same values env-vars sets for published bindings. The cuda.bindings tests for 3.15 and 3.15t ran in the 12.9.10 and 13.4.4 release CI.
• Cherry-pick Add pathfinder support for cupti64_2026.3.1.dll (CTK 13.4.1) #2896 and Add cusparseLt_13.dll #2982: pathfinder learns cupti64_2026.3.1.dll and cusparseLt_13.dll. Current CTK wheels ship these names, and the Windows pathfinder tests fail without them. 13.4.x carries the same fixes.
• cuda_core/pyproject.toml: add the Python 3.15 classifier. requires-python stays >=3.10.
• Docs: 1.2.2 release notes, and the install and support pages list Python 3.10 - 3.15. Python 3.15 needs cuda-bindings 12.9.10 or newer for CUDA 12, or 13.4.4 or newer for CUDA 13.

Release plan

Remove [no-ci] and run CI once the 12.9.10 cp315 wheels are on PyPI, merge here, tag cuda-core-v1.2.2 on the merge commit, wait for the tag-triggered CI run, run the release workflow in dry-run mode, then release. Follow-up #3109 adds 1.2.2 to the docs version switcher on main, with the 1.2.2 release notes and the Python 3.15 classifier.

🤖 Generated with Claude Code

[mdboom]

I guess we should make a cuda_bindings 12.9.10 release as well...?

[mdboom]

See this preparation for the 12.9.10 release: #3112

[github-actions]

Doc Preview CI
🚀 View preview at https://nvidia.github.io/cuda-python/pr-preview/pr-3108/
https://nvidia.github.io/cuda-python/pr-preview/pr-3108/cuda-core/
https://nvidia.github.io/cuda-python/pr-preview/pr-3108/cuda-bindings/
https://nvidia.github.io/cuda-python/pr-preview/pr-3108/cuda-pathfinder/
Preview will be ready when the GitHub Pages deployment is complete.

[rwgk]

This looks good to me, pending Python 3.15 support for CUDA 12.

(Note that I triggered a rerun to resolve a lychee flake in the doc build; we don't have #2993 on this branch; which is fine.)