Add "netlify-website-optimizer" check

[continue]

Adds the netlify-website-optimizer check to this repository.

This check will be synced from .continue/checks/netlify-website-optimizer.md and can be customized by editing the file directly.

---

Opened via Continue Hub

---

Summary by cubic

Adds the netlify-website-optimizer check to audit PR preview vs production Netlify deploys and block risky performance regressions. The check lives in .continue/checks/netlify-website-optimizer.md and uses netlify/netlify-mcp.

• New Features
  • Quick triage thresholds: <10% auto-approve, 10–50% review, >50% block.
  • Fetches deploy URLs and asset sizes via netlify/netlify-mcp; totals JS/CSS/images from headers.
  • Flags config issues: disabled minification/tree-shaking, production sourcemaps, missing cache headers.
  • Outputs clear reports with links and actionable fixes.
  • Handles pending/failed deploys with retries and helpful messages.

^{Written for commit f139ec6. Summary will update on new commits. Review in cubic}

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.