Modify Architecture to use Langgraph & tools instead of forced RAG & Search

[brettv30]

Modify Git Buddy's underlying architecture to use Langgraph and follow a more agentic approach where the agent can decide if it wants to retrieve documents from the vector DB and if it needs to do additional searches or if it has the answers in its pre-existing knowledge base. i.e. Create an agent with tools using Langgraph instead of multiple chains with forced RAG using Langchain