Add skills/anysearch (vendored from anysearch-ai/anysearch-skill v3.1.1)
so agents get general/anonymous search, parallel batch search, vertical
domain search, and full-page extract. Includes MAINTENANCE.md and
docs/anysearch-skill.md. No internal/, ui/, or migration changes.
Disclosure: AnySearch Open Source Bounty Claim goclaw#001.