## Summary
Standardize the repo's Node contract on 24 while centralizing workflow
resolution through `.nvmrc` so local setup, CI, and package metadata
stay aligned from one version file.
## Changes
- **What**: Add `package.json` `engines.node = 24.x`, switch every
`actions/setup-node` workflow in the repo to `node-version-file:
'.nvmrc'`, and update contributor and Playwright docs to point to
`.nvmrc` as the Node source of truth.
## Review Focus
The workflow behavior should be unchanged apart from sourcing the Node
version from `.nvmrc` instead of repeating literals like `20`, `22`,
`24.x`, or `lts/*`. GitHub's formatter also moved the new `engines`
block to the package metadata section near the end of `package.json`.
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Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: Alexander Brown <drjkl@comfy.org>
