Summary

CI currently runs only ubuntu-latest (which is x86_64). We don't exercise Linux aarch64 at all, even though Linux aarch64 is a supported install target per the README's Supported Platforms section.

This is a complement to the wheel pre-flight script (also added in the same PR that files this issue): the pre-flight catches when a dep's wheel disappears for our supported platforms via dep-resolution check; this issue adds actual end-to-end test execution on Linux aarch64 itself.

Background

GitHub now provides ubuntu-24.04-arm as a hosted runner (available on the free tier for public repos). Adding it to the matrix:

• Verifies wheels actually install and run end-to-end on Linux aarch64 (not just resolve)
• Catches any Linux aarch64-specific runtime behaviour issues
• Reduces our exposure to the same kind of "CI masked a real platform issue" trap that Install fails on macOS arm64 with Apple Clang 15: z3-solver==4.16.0.0 has no prebuilt wheel + source build hits std::format #691 surfaced for macOS

Scope

Add one matrix entry: ubuntu-24.04-arm × Python 3.12 (single Python version is enough — this is platform coverage, not Python-version coverage).

Cost

Roughly +1 job per CI run. Linux ARM runners are typically cheaper than macOS minutes.

Related

• Companion issue: Linux aarch64 install requires glibc 2.38+ — Ubuntu 22.04 LTS aarch64 not supported #701 — Ubuntu 22.04 LTS aarch64 not supported (glibc baseline)
• Install fails on macOS arm64 with Apple Clang 15: z3-solver==4.16.0.0 has no prebuilt wheel + source build hits std::format #691 — the original "CI is masked from a real platform" symptom that motivated this work