Add CI for supported Node.js versions

[infeng]

Summary

• run tests, lint, builds, and package checks for pull requests and master
• cover the supported Node.js 22 and 24 LTS releases
• pin both the main package and SSR fixture to the public npm registry
• reject lockfiles that contain the internal bnpm.byted.org registry
• restrict the workflow token to read-only repository contents
• cancel superseded runs on the same branch

Validation

• main package: npm ci --ignore-scripts
• SSR fixture: npm ci --ignore-scripts
• npm test -- --runInBand (38 tests)
• npm run lint
• npm run build
• npm pack --dry-run
• all lockfile hosts resolve to registry.npmjs.org