Add GitHub Actions workflow for npm package publishing

[brodogg94-code]

This workflow runs tests and publishes a Node.js package to GitHub Packages upon release creation.

Description

Issue(s) fixed

Fixes #

Preview

Checklist

• If this PR updates or adds documentation content that changes or adds technical meaning, it has received an approval from an engineer or DevRel from the relevant team.
• If this PR updates or adds documentation content, it has received an approval from a technical writer.

External contributor checklist

• I've read the contribution guidelines.
• I've created a new issue (or assigned myself to an existing issue) describing what this PR addresses.

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Note

Introduces automated CI/CD for Node.js package releases.

• New workflow /.github/workflows/npm-publish.yml triggered on release: created
• build job (Node 20): npm ci and npm test
• publish-npm job depends on build; configures npm registry, runs npm ci, then npm publish using secrets.npm_token

^{Written by Cursor Bugbot for commit 33fe5ae. This will update automatically on new commits. Configure here.}

[vercel]

@brodogg94-code is attempting to deploy a commit to the Consensys Team on Vercel.

A member of the Team first needs to authorize it.

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

[m4sterbunny]

@joshuafernandes I assume this would be more in the remit of gha repo than any individual repo. Do you want this or should I close?