GitHub Actions is deprecating Node.js 20, with Node 24 becoming the
default runner on June 2, 2026. This updates the action to run on
the Node 24 runtime.

Changes:
- action.yml: node20 → node24
- esbuild target: node20 → node24
- @types/node: ^20 → ^24
- @actions/* deps bumped to their Node 24-compatible versions
  (highest CJS-compatible releases, avoiding the ESM-only latest)

The @actions/* bumps also resolve the punycode deprecation warning
(DEP0040) that Node 24 triggers with the older dependency chain.

Closes #172

Co-authored-by: Adam White <adam0white@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

fix(ci): pin `actions/checkout@v6.0.2` by commit hash

Support for Node.js version 24 was added in v5.

fix(ci): pin `autofix-ci/action@v1.3.2` by commit hash

Used `v1.3.2` to avoid the hostname change.

Support for Node.js version 24 is not yet available.

Also:
- pin `actions/checkout@v6.0.2` by commit hash

fix(ci): pin `actions/publish-action@v0.4.0` by commit hash

Support for Node.js version 24 was added in `v0.4.0`.

Also:
- pin `actions/checkout@v6.0.2` by commit hash