change gradio api base

Remove useless importings from generator.py

change summary model to openai gpt-4o-mini

Change file location to meet docker and hugging face space needs

add app port

move app.py to root directory

Clean test jupyter notebook files

change main.py to FastAPI + Gradio mount point; Test the functions locally and fix some bugs

Updates libraries impporting (especially langchain), add more apis, complete test for generation

Re-organized structures. Use chapter and summary managers to handle chapter and summary generatio, save, update and some further logic.

Change local model tiny llama to use OpenAI api with 4o-mini, change summary model to faster local model. (OpenAI api is an option as well)

Use langchain vectorstores library to replace previous faiss index class

Built FAISS, now working on Langchain integration

Local Reasoning + Generator Module (1st version), working on FAISS Memory