TL;DR — Collaborative Whiteboard

Design a real-time collaborative whiteboard similar to Figma or Miro where multiple users simultaneously draw shapes, add text, move objects, and see each other's cursors in real-time. The system must handle concurrent edits without conflicts, synchronize state across all participants within 100ms, and support undo/redo that works correctly in a multi-user context. Key features: Real-time drawing: shapes, freehand, text, images, connectors. Multi-user concurrent editing with live cursor positions.