Add a LangChain/Langgraph agent

[MichaelClifford]

We should add an agent to this repo that uses langchain/langraph to connect to the github MCP server.

[RHETbot]

This issue requests the addition of a LangChain/LangGraph-based agent to connect to the GitHub MCP server. Recent research indicates that the langchain-mcp-adapters library is available, providing a lightweight wrapper that facilitates integration of MCP tools with LangChain and LangGraph. This resource simplifies the development process by enabling seamless connection to MCP servers.

Next steps include:

1. Clarifying the specific workflows and data requirements with the user.
2. Reviewing the langchain-mcp-adapters library and testing its capabilities.
3. Developing a prototype agent to connect to the MCP server, using the adapters.
4. Sharing the prototype with maintainers for feedback and documentation.
5. Finalizing the implementation and deploying it as part of the repository or as a standalone example.

Leveraging the existing langchain-mcp-adapters will significantly accelerate development and ensure compatibility with MCP servers.