Rebuilds MCP integration layer following Anthropic's official plugin pattern:
- New .mcp.json with 6 HTTP connectors (Notion, Canva, Webflow, Slack, Gmail, Calendar)
- New CONNECTORS.md with ~~category connector references
- Minimal plugin.json (4 fields, matching Anthropic's format)
- Agent names normalized to kebab-case for Cowork routing
- Removed non-standard skill_type field from skill frontmatter
- Un-gitignored .mcp.json (HTTP URLs, no credentials)

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