LLM Framework

This is Keen CLI, a CLI-based coding agent. Check the design in @.ai-interactions/prompts/phase-1/output-1_rfc.md and understand more about the project.

Currently, for LLM integration, we are using langchain-go. But we want to reevaluate this decision. Explore the landscape of LLM frameworks in Go and suggest some alternatives that are more suitable for this project.

I want to pick up a framework that is open-source, well maintained, and has a good community. It should also be extensible and easy to use. It should also be able to work with many different LLM providers.