Add MCP server package for Ghost UI registry

[nahiyankhan]

Summary

• New packages/ghost-mcp package exposing Ghost UI's component registry via Model Context Protocol
• 5 MCP tools: search_components, get_component, get_install_command, list_categories, get_theme
• 2 MCP resources: ghost://registry (JSON), ghost://skills (markdown)
• Stdio transport, runnable via npx @ghost/mcp
• Bundles registry.json and skills.md at build time, reads component source from sibling package

Test plan

• pnpm install && pnpm --filter @ghost/mcp build succeeds
• pnpm typecheck passes from root
• Smoke test: pipe JSON-RPC initialize message to node packages/ghost-mcp/dist/bin.js
• Configure in Claude Code and verify tool calls work

🤖 Generated with Claude Code