Reduce GitHub Actions macOS worker demand

[alexreinking]

Summary

We can only run five concurrent macOS jobs at a time. As such, anything that isn't macOS-specific needs to move off them in order to keep those resources free for work that is.

• testing-make.yml: drop unused uv/Python setup (the Makefile build has no Python dependency), and restrict the macOS matrix leg to make test_apps (which still builds Halide via the distrib dependency), leaving the full test suite on Linux. Reduced from ~40m to ~10m.
• Move clang-tidy.yml off macos-latest onto ubuntu-24.04, building wabt from source with -DCMAKE_POSITION_INDEPENDENT_CODE=ON -DUSE_INTERNAL_SHA256=ON to avoid both the missing-PIC and OpenSSL-config gaps in Ubuntu's wabt package. Increased from ~43m to ~70m, but on Linux.

Test plan

• Validated run-clang-tidy.sh end-to-end in a clean Ubuntu 24.04 x86_64 Docker container (matching the ubuntu-24.04 GitHub runner), using the exact package/build steps now in clang-tidy.yml: full 392/392 file pass, Success!.
• CI green on this PR.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.17%. Comparing base (ceea694) to head (6a18563).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9280      +/-   ##
==========================================
- Coverage   70.26%   70.17%   -0.10%     
==========================================
  Files         257      257              
  Lines       79106    79136      +30     
  Branches    18954    18979      +25     
==========================================
- Hits        55583    55532      -51     
+ Misses      17885    17848      -37     
- Partials     5638     5756     +118     

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[abadams]

I'm inclined to fix linter errors in the tutorial's simd code if possible. How should I repro locally?

[alexreinking]

I'm inclined to fix linter errors in the tutorial's simd code if possible. How should I repro locally?

I used Docker. Just ask Claude to run run-clang-tidy.sh in an x86 Ubuntu Docker container.

[abadams]

Assuming I repro and fix, should I push to this branch or open a separate PR?

[alexreinking]

Assuming I repro and fix, should I push to this branch or open a separate PR?

Push here, might as well