chore(ci): clean up test workflow matrix

[premsgr]

Summary

• standardize formatting in the test workflow for clearer step naming and structure
• update the CI test matrix to run on Node.js 20, 22, and 24 only
• keep test/build/install job behavior unchanged apart from the supported runtime versions

Test plan

• Let pre-commit checks run successfully during commit
• Verify GitHub Actions Test suite workflow passes on this branch