Handle scanner POSTs to catch-all routes

[kentcdodds]

Summary

• Patch the packaged workshop app server build after install so the root catch-all route has an action that throws a normal 404 response for POST submissions.
• Add a Playwright regression test for scanner-style POSTs to /_middleware.
• Keep the filter narrow by preserving existing route behavior and avoiding a broad Sentry getInternalRouterError suppression.

Sentry

• epicshop issue EPICSHOP-F0 / 7447885629
• Examples included POST probes for /_middleware, /.action, /RSC/...txt, /_next, /__rsc, /_rsc, and /_next/image.

Validation

• npm test -- catch-all-posts.spec.js (from epicshop/)
• npm run lint
• npm run typecheck