fix: scrub all remaining declawed/vercel refs

- Regenerate package-lock.json with leashed name
- Replace docs/showcase.html with clean harness version
- Remove stale plan docs with old naming

Zero "declawed", "Shield", or "vercel.app" references remain.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dormstern