ci: reduce GitHub Actions costs by ~85% on PRs

[VinciGit00]

Summary

• OS matrix on PRs: reduced from 3 OS (ubuntu/macOS/windows) to ubuntu-only. macOS (10x cost) and Windows (2x cost) run only on push to main.
• Python versions: reduced from 3.10/3.11/3.12 to 3.10/3.12 (testing range extremes only).
• Benchmarks: now run only on push to main, not on every PR.
• Code quality checks: run only on push (removed duplicate code-quality.yml workflow already present in test-suite.yml).
• Playwright: removed unnecessary install from benchmark job.

Cost impact

Scenario	Before	After
PR unit tests	9 jobs (3 OS × 3 Py) ≈ 39× base cost	2 jobs (1 OS × 2 Py) = 2×
PR total jobs	~16	~6
Push to main	~16	~12

Test plan

• Verify PR-triggered workflows run only on ubuntu with Python 3.10 and 3.12
• Verify push-to-main workflows still run the full OS matrix
• Verify benchmarks only trigger on main push
• Verify code quality checks still run on push events

🤖 Generated with Claude Code

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

• .github/workflows/code-quality.yml