feat: add GitGuardian MCP server

[mathieubellon]

Motivation and Context

Bring incident metadata in the developer and agent context for efficient remediation

How Has This Been Tested?

The server was tested with Claude Sonnet 4. We examined three different scenarios: scanning the local project for hardcoded secrets, remediating incidents related to the current repository, and inserting a honeytoken to secure the project.

Breaking Changes

No breaking changes, this is our first publication

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

[olaservo]

Thanks for your contribution to the servers list. This has been merged in this combined PR: #2374

This is a new process we're trying out, so if you see any issues feel free to re-open the PR and tag me.