[WIP] Add a new dropdown in the top navigation bar in the frontend. Dropdown list - Agent (default) - Workflow * by default agent mode is selected and it connects to the sse backend in the langgraph_backend/ * when user changes the mode to workflow, the frontend should change the connectors and switch to the old websocket backend in backend/ * since backend/ socketio server runs on a different url path it will be easy to switch - #5