chore: remove stale Resend overrides (#17)

The openapi override (slug 'resend') wins domain-level dedup over the richer
'discovered' feed and collapses resend.com to a single OpenAPI record,
suppressing its MCP and CLI surfaces. The mcp override produces zero catalog
records (dead). Removing both restores resend.com to MCP + OpenAPI + CLI from
the discovered feed, which Resend now also backs with an owner-declared
/.well-known/integrations.json.

Verified via scripts/normalize.ts:
  with overrides    -> mcp.json: 0 resend; index: openapi/resend only
  without overrides -> mcp.json: 1 resend; index: MCP + OpenAPI + CLI

Author: dielduarte