Add a Claude Code plugin (`plugins/mcp-apps/`) for distribution via the
plugin marketplace. The plugin provides the "Create MCP App" skill that
guides the agent through building MCP Apps with interactive UIs.
The skill includes:
- Instructions to clone SDK repo for reference templates
- Framework selection guidance (React, Vanilla JS, Vue, Svelte, etc.)
- Tool visibility configuration (`_meta.ui.visibility`)
- Host styling integration patterns
- Testing workflow using `basic-host`
- Common mistakes to avoid
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>