Improve Github Action Workflow

[AliceR]

@danielfdsilva spent time in #24 improving the GitHub workflow.
To keep our git history clean and make reviews easier, we should extract the workflow improvements into their own PR, based on the develop branch.

GitHub Actions Workflow Updates (.github/workflows/checks.yml)

• Add descriptive header comments explaining the workflow purpose
• Update trigger conditions:
  • Remove push trigger on main branch
  • Update pull_request types to: opened, synchronize, reopened, ready_for_review
  • Add concurrency controls to cancel in-progress runs for the same ref
• Update Node.js version strategy:
  • Remove hardcoded NODE environment variable
  • Use node-version-file: '.nvmrc' to read version from .nvmrc file
• Update GitHub Actions to latest versions:
  • actions/checkout@v2 → actions/checkout@v4
  • actions/setup-node@v1 → actions/setup-node@v4
  • actions/cache@v2 → actions/cache@v4
  • Remove deprecated styfle/cancel-workflow-action (replaced by concurrency)
• Simplify cache key:
  • Remove cache-name environment variable
  • Use ${{ runner.os }}-build-${{ hashFiles('**/package.json') }}
• Update job commands:
  • Use explicit yarn run lint instead of yarn lint
  • Use explicit yarn run test instead of yarn test
  • Use explicit yarn run build instead of yarn build
  • Fix build job step name: "Test" → "Build"
• Ensure build job depends on test job (not changed, but verify)

References

• Original PR: Alpha 11 #24
• Target branch: develop

Notes

This is purely infrastructure/tooling changes with no functional code changes to the library itself.