introduce the session into the frontend api

introduce the delete document funcs

refactor the config input

introduce the yaml for configuration

further refactor

fix typo

refactor db creation & centralize the config.py

refactor

refactor code

introduce chain of throught

fix some issues

add dspy

Refactor core structure and add new RAG modules

Add database and model to the project

Refactor the code structure to allow using both gemini and Deepseek.

mark milestone first done

first commit