Updating assitant with tool

Switch to using LangChain Runnable for the OpenAI client

Moving client and thread to global scope

Updating RAQA chain from session

Add PDF upload Action and Assistants API

Reverting to previous pipeline to avoid dict has no invoke error

Updating prompt and RAG pipeline for default virtual student behavior

Merge branch 'main' of https://huggingface.co/spaces/ymath/Teach2LearnVirtualStudent

initial commit

Adding base files for Chainlit app with RAG pipeline

Initial commit