Replace fixed sidebar with floating action buttons (menu + add node) in
bottom-left corner. Sidebar and node panel now slide in as overlay drawers
with backdrop dismiss, capped width for small screens, and slide animations.
Express API server wrapping existing store/graph core with REST endpoints
for nodes, edges, graph, and search. React + Vite portal with React Flow
for interactive graph visualization, Tailwind CSS styling, and full CRUD UI
(sidebar, node panel, add/link modals, search bar, toast notifications).
