Add env config, JWT checks & frontend fixes

Add JWT refresh auth, Redis & provider support

Normalize OpenAI API URL and update UI/docs

Document LangGraph4j engine and Skills system

Add skill system and LLM config APIs

Add tutorial section to README and resume doc

Integrate LangGraph4j workflow engine

Update architecture diagram in README

Update README.md

Move documentation files to docs directory

Update README.md

Refactor LLM node executors to use Spring AI

Add architecture diagram to README

Update README image links to local files

Revamp README with enterprise-level documentation