docs: Document npm+npx deployment pattern for Node.js MCP servers

[bryankthompson]

Summary

Add minimal documentation for an alternative Node.js deployment pattern using npm and npx instead of bundling node_modules.

Motivation

This pattern is already in production use by multiple MCP servers but was undocumented. It complements PR #161 which documents the equivalent uvx pattern for Python.

Changes

MANIFEST.md

• Add npx configuration example alongside traditional Node.js example

README.md

• Add concise section on npm-based deployment
• Include trade-offs comparison table
• Link to example implementation

examples/npx-node/

• Complete minimal working example
• Demonstrates manifest and package.json configuration
• Shows required bin entry setup

Pattern Overview

Manifest configuration:

{
  "mcp_config": {
    "command": "npx",
    "args": ["-y", "--package=your-package", "your-bin-command"]
  }
}

Benefits:

• Smaller bundle sizes (< 50 KB vs 50-300 MB)
• Automatic updates from npm
• Zero bundle maintenance

Trade-offs:

• Requires internet on first launch
• 30-60 second initial download

Testing

• ✅ Verified working with multiple production implementations
• ✅ Confirmed npx invocation from Claude Desktop
• ✅ Validated manifest schema compliance with mcpb validate

🤖 Generated with Claude Code