ci: upgrade GitHub Actions to Node.js 24 runtime

[DrWheelicus]

What Changed

Upgrade GitHub Actions to Node.js 24 ahead of the June 2 2026 deadline when GitHub will force all actions to run on Node.js 24.

Upgraded to new major versions (Node.js 24 releases available):

• amannn/action-semantic-pull-request v5 → v6
• actions/cache/save and actions/cache/restore v4 → v5

Added FORCE_JAVASCRIPT_ACTIONS_TO_NODE24 env workaround for actions whose upstream maintainers have not yet shipped a Node.js 24 release:

• googleapis/release-please-action@v4 — PR #1192 pending
• actions/dependency-review-action@v4 — PR #1081 pending
• davelosert/vitest-coverage-report-action@v2 — no upstream PR yet

Type of Change

• Bug fix
• Feature
• Refactor
• Documentation
• Test-only change
• CI/CD or tooling

Related Issues

N/A

Validation

• npm run lint
• npm run typecheck
• npm test
• npm run build

No application code changes — validation is CI pipeline execution on this PR.

Behavior and Risk

• User-visible behavior: None — CI/CD only
• Backward compatibility impact: None
• Security implications: None — actions are pinned to major version tags from the same publishers

Screenshots / Logs (if applicable)

The deprecation warning this PR eliminates:

Node.js 20 actions are deprecated. The following actions are running on Node.js 20 and may not work as expected: googleapis/release-please-action@v4. Actions will be forced to run with Node.js 24 by default starting June 2nd, 2026.

Checklist

• I followed CONTRIBUTING.md
• I kept changes focused and minimal
• I did not include secrets, tokens, or sensitive data
• I added/updated tests where appropriate — N/A
• I updated docs when behavior changed — N/A

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	52.77%	419 / 794
🔵	Statements	52.77% (🎯 30%)	419 / 794
🔵	Functions	75%	36 / 48
🔵	Branches	70.65%	65 / 92

File Coverage

No changed files found.

Generated in workflow #41 for commit c29a1f6 by the Vitest Coverage Report Action