I'm building Small Room Solver, a free browser tool for trying furniture layouts before moving everything around. You draw your room, enter furniture measurements, move things around in 2D and open a 3D preview. No signup needed; edits stay in your browser unless you choose to share a snapshot. I used OpenAI Codex for implementation and debugging. The stack is Astro, React and TypeScript, with SVG for the 2D editor and Three.js through React Three Fiber for 3D. Drafts save locally in IndexedD...