Alpha release of @wpengine/hwp-toolbar NPM package #435

Acceptance Criteria

• @wpengine/hwp-toolbar is publicly available to use under a pre-release
• This core HWP package is framework agnostic (vanilla core plus an optional ./react entry; ships from src with no build step)

Current state

The package isn't on npm yet, but packages/toolbar/README.md already documents installing it from npm. There's no npm release setup in the repo: release-please-config.json only covers the plugins, and no workflow runs npm publish.

Checklist

• Add packages/toolbar to release-please-config.json as a prerelease package, following how faustjs releases its npm packages
• Add an npm publish job that runs when a toolbar release is created, using npm trusted publishing (GitHub Actions OIDC) so no npm token is stored in the repo
• Confirm publish access for the package under the @wpengine npm org and configure the trusted publisher on npmjs.com
• Publish the first alpha (e.g. 0.1.0-alpha.0) under a non-latest dist-tag (alpha or next)
• Verify the README install and quick-start steps work against the published package

Related

• chore(packages): Add linting and code quality automation #441: linting and code quality for packages/, ideally landed first