Add Sub-Agents MCP to Community Servers

[shinpr]

Description

This PR adds Sub-Agents MCP to the Community Servers README.

Motivation and Context

Sub-Agents MCP enables users to define focused AI agents in Markdown for specialized tasks. It addresses the growing need for multi-agent orchestration by providing context
isolation and lightweight agent definitions that can be reused across MCP-compatible tools.

How Has This Been Tested?

Tested with:

• Claude Code
• Cursor CLI
• Gemini CLI

Types of changes

• Documentation update

Checklist

• I have read the MCP Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

[domdomegg]

I'm closing this as we're no longer accepting updates to the servers README. Going forwards, we recommend submitting MCP servers to the MCP registry - keen to see your server there :)