fix(ci): restrict UBI10 build, test, and manifest to CUDA 13.x only

[ramakrishnap-nv]

Summary

nvidia/cuda UBI10 base images are only published for CUDA 13.x — neither Docker Hub nor NGC provide them for any 12.x release. The CI was failing with not found when attempting to build the UBI10 image for CUDA 12.9.0.

[github-actions]

CI Test Summary

✅ All 13 test job(s) passed.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: 9182d2f7-cad0-40f3-967a-1dbcaafae24f

📥 Commits

Reviewing files that changed from the base of the PR and between 5717c48 and 300c42a.

📒 Files selected for processing (2)

• README.md
• docs/cuopt/source/_static/install-selector.js

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📝 Walkthrough

Walkthrough

This PR gates UBI10 build, test, and manifest generation on CUDA 13.x and updates the README and install selector to remove CUDA 12 UBI10 references.

Changes

UBI10 CUDA 13 gating

Layer / File(s)	Summary
Gate workflow UBI10 steps .github/workflows/build_images.yaml, .github/workflows/test_images.yaml	Adds CUDA 13.x conditions to the UBI10 build, push, and test workflow entries.
Gate manifest generation ci/docker/create_multiarch_manifest.sh	Wraps UBI10 multi-arch and release manifest creation in a CUDA_MAJOR 13 check and adds a skip message for other CUDA majors.
Update UBI10 docs and selector README.md, docs/cuopt/source/_static/install-selector.js	Removes CUDA 12 UBI10 container entries, updates UBI10 availability notes, and changes UBI10 fallback handling to cu13-ubi10.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: limiting UBI10 CI and manifest handling to CUDA 13.x.
Description check	✅ Passed	The description is directly related to the change and explains the CUDA 12.x UBI10 failure it fixes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/ubi10-cuda13-only

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