vinext check reports false incompatibilities when other toolchains' build output exists (.open-next/, .wrangler/, .output/)

[JamesbbBriz]

Context

Following the documented OpenNext → vinext migration path leaves the previous toolchain's build output next to the project root (.open-next/, .wrangler/, .output/, and friends). vinext check walks those directories during the compatibility scan and reports the bundled worker code as application source.

Observed

• Imports inside .open-next/server-functions/... (e.g. next/dist/server/next-server.js) flagged as unsupported
• CJS globals inside those bundles flagged as blockers
• The overall compatibility percentage dragged down — we measured 79% on a Payload 3 app that was fully compatible once the stale output was deleted

Expected

The scan should skip build output from other toolchains the same way it skips node_modules/.next/dist; migration artifacts are deleted during the migration anyway.

Workaround

Delete .open-next/ (and other stale output) before running vinext check.

Fixed by #3231.