Harden repository and reposition as MCP Skill Registry

[fractional-pm]

Summary

This PR transforms MCP Registry into a production-grade Skill Registry for MCP-compatible AI agents.

Included changes

• Repositioned project messaging around reusable skills
• Updated package metadata and scripts
• Rewrote README
• Replaced landing page with Skill Registry marketing site

Follow-up

Additional governance files, CI workflows, schema validation, and GitHub Pages deployment can be added in a subsequent PR if desired.

[fractional-pm]

Follow-up requested: add MCPs from Docker Hub, but only from official sources.

Implementation note:

• Do not ingest arbitrary Docker Hub search results.
• Only import images from verified/official publishers or official MCP project references.
• Suggested next PR: add registry/dockerhub.official.json with fields like name, publisher, docker_image, source_url, verification_status, license, and notes.
• Suggested policy: every imported Docker image must include an official source URL and a human-verifiable ownership trail.

I avoided broad scraping because Docker Hub search results do not reliably distinguish official MCP images from community or lookalike packages.