CI: Fix pathfinder CI infrastructure and remove redundant component testing

[Copilot]

Fixes #810 by updating both Linux and Windows test workflows to always fetch the cuda-pathfinder wheel from the latest successful run on the main branch, rather than from the current branch's build artifacts. Additionally removes redundant testing of components that are not actively maintained in this branch.

Problem

The current CI design has issues with outdated artifacts and redundant testing:

1. Outdated pathfinder artifacts: The 12.9.x branch test workflows download cuda-pathfinder from the same branch as other components. However, cuda-pathfinder is only actively maintained on the main branch, so using artifacts from the 12.9.x branch could lead to outdated or inconsistent pathfinder functionality.

2. Redundant component testing: The workflows run tests for cuda-pathfinder and cuda.core on backport branches, but since these components are only developed on main, these tests are redundant and don't add value.

Solution

This PR modifies both test-wheel-linux.yml and test-wheel-windows.yml to:

1. Replace the existing artifact download step for cuda-pathfinder with new steps that fetch from the main branch
2. Follow the existing pattern used by the "Download cuda-python & cuda.bindings build artifacts from the prior branch" steps
3. Ensure cross-platform compatibility with proper bash/PowerShell implementations
4. Remove all pathfinder and cuda.core test steps since the focus should be on ensuring cuda.bindings 12.x works correctly with the latest versions of these components, not testing them independently

The new pathfinder download steps:

• Install GitHub CLI if not available
• Query the latest successful CI run on the main branch
• Download the cuda-pathfinder-wheel artifact from that run
• Place it in the expected ./cuda_pathfinder directory

Key Features

• Consistent behavior: Both workflows now guarantee they use the same, up-to-date pathfinder from main
• Focused testing: Removed redundant component tests; workflows focus on cuda.bindings compatibility with latest versions
• Error handling: Proper validation that the latest run ID is found before attempting download
• Backward compatibility: Maintains the same directory structure expected by downstream workflow steps
• Follows existing patterns: Uses the same approach as the existing cross-branch artifact fetching logic

This change ensures that 12.9.x branch testing always uses the maintained implementations from main for compatibility testing with cuda.bindings, while eliminating redundant testing and the risk of using stale code from components not maintained in this branch.

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[leofang]

@copilot

[leofang]

@copilot address the comments above

[Copilot]

@copilot address the comments above

Addressed both comments: consolidated GitHub CLI installation in Linux workflow (removed duplication) and fixed step ordering in Windows workflow to ensure gh is available before pathfinder download. Changes made in commit c110dcf.

[leofang]

/ok to test c110dcf

[leofang]

@copilot please remove all pathfinder test steps from the test workflows. As mentioned we only develop (and thus) pathfinder on the main branch. So for the backport branch, the focus is to ensure cuda.bindings 12.x can run correctly with the latest pathfinder.

[Copilot]

@copilot please remove all pathfinder test steps from the test workflows. As mentioned we only develop (and thus) pathfinder on the main branch. So for the backport branch, the focus is to ensure cuda...

Removed all pathfinder test steps from both Linux and Windows test workflows as requested. The workflows now focus on ensuring cuda.bindings 12.x works correctly with the latest pathfinder from main, without redundantly testing pathfinder itself. Fixed in commit 7f46e6c.

[leofang]

/ok to test 7f46e6c

[leofang]

@copilot for the same reasons, we should remove the cuda.core tests from both test workflows. Only cuda-bindings and cuda-python 12.x are maintained in this branch.

[Copilot]

@copilot for the same reasons, we should remove the cuda.core tests from both test workflows. Only cuda-bindings and cuda-python 12.x are maintained in this branch.

Removed all cuda.core test steps from both Linux and Windows test workflows as requested. The workflows now focus only on cuda-bindings and cuda-python 12.x testing, which are the components maintained in this branch. Fixed in commit 402759e.

[rwgk]

Just a question about a potential simplification. If it looks interesting, we could do that in a separate PR. I see the code is just moved around in this PR.

[rwgk]

Did you look into using an existing action?

This is from ChatGPT, I didn't try it out:

      - name: Setup GitHub CLI
        uses: actions4gh/setup-gh@v1
        with:
          gh-version: latest         # or specify "2.65.0", etc.
          token: ${{ secrets.GITHUB_TOKEN }}

[leofang]

It seems setup-gh is no longer maintained... 😢 https://github.com/actions4gh/setup-gh

[leofang]

FWIW we already have a install_unix_deps action. Perhaps we could just move this bits there to allow using it to install gh?

[leofang]

/ok to test 402759e