add missing docstrings

updates for hf tts loader

add docstring comments to compute_service

update a copy of the default generation config with runtime values

convert the language name to lowercase before getting the language code

update environment setup section

update environment_cpu.yml

update roadmap in README

update overall-system diagram

update README

retrieve supported languages from bot-backend for frontend-app

fix langgraph flow issues

fix response format issue with new langchain changes

corrected comments in bot-backend main file

adopt langchain latest usage patterns