This commit adds detailed OCamldoc annotations to the Mcp.mli interface file, based on the Model Context Protocol specifications. The annotations provide:

- Detailed module overview explaining the MCP architecture and components
- Thorough documentation for all types, modules, and functions
- Explanations of core protocol concepts
- JSON format examples using OCamldoc verbatim blocks
- Parameter documentation with @param tags

The annotations will improve code understandability and support OCamldoc generation.

🤖 Generated with [Claude Code](https://claude.ai/code)

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