Add MSSQL MCP server to Community Servers

[JexinSam]

Description

Adding MSSQL MCP server implementation to Community Servers section in README.md

Server Details

• Server: mssql-mcp-server (new addition to community servers)
• Changes to: README.md only - adding entry to Community Servers list

Motivation and Context

Adding reference to a new community implementation of an MCP server that provides MSSQL database integration. This addition increases the visibility of available MCP servers and provides another database integration option for the community.

How Has This Been Tested?

This is a documentation update only - adding a reference to an existing, tested implementation.

The referenced MSSQL MCP server itself has been thoroughly tested:

• Automated testing via GitHub Actions workflow
• Tests run against MSSQL 2019 Express in a containerized environment
• Tested with Python 3.11 and 3.12
• Full test suite runs with pytest
• Integration tested with Claude Desktop as the LLM client
• Includes verification of module installation and dependencies

Breaking Changes

None - this is a documentation addition only.

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