Update README: Add MemOS API Service MCP to community servers

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Description

Added MemOS API service MCP to README

Server Details

• Server: https://github.com/MemTensor/memos-api-mcp

About MemOS

• MemOS (Memory Operating System) is a memory management operating system designed for AI applications.
• official website: https://memos.openmem.net/
• open-source code implementation for underlying service: https://github.com/MemTensor/MemOS

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• 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

Additional context