Nested npm test packages inside Yarn PnP repos must isolate NODE_OPTIONS

What happened

The slate-browser POC used a nested support package with its own npm install, Vitest browser config, and Playwright dependency, but the parent Slate repo runs on Yarn PnP.

That caused two real integration failures:

1. root NODE_OPTIONS / Yarn PnP loader polluted nested npm + Vitest execution
2. Playwright browser install had to match the repo’s Playwright version, not an ad hoc npx playwright install

What fixed it

1. Root scripts explicitly unset NODE_OPTIONS before entering the nested npm package.
2. Browser provisioning uses the repo-scoped Playwright binary: yarn exec playwright install chromium

Reusable rule

If a Yarn PnP repo hosts a nested npm-based testing package:

• do not assume root env is harmless
• isolate NODE_OPTIONS
• install Playwright browsers with the repo’s own Playwright version

Otherwise the test stack will look fine until the first real browser lane runs, then fail for reasons that have nothing to do with the product code.