Context

GitHub is actively deprecating Node 20 runners. By September 2026, workflows relying on Node 20 will fail entirely. For this repo, this primarily impacts our Markdown linters, spelling checkers, and any static site generation steps. We need to bump our actions to stay ahead of the deprecation cliff.

Tasks

• Audit all .github/workflows/*.yml files for deprecated Node versions.
• Bump core actions (e.g., actions/checkout to v4 and actions/setup-node to v4).
• Update the node-version matrix to target Node 22 (LTS) or Node 24.
• Drop Node 18 and 20 from any testing/linting matrices.