v0.3.1
Fix fullscreen height collapse on claude.ai web
- Use containerDimensions from host context instead of 100vh
- Remove #root div, render React directly to body
- Set explicit height on html/body in fullscreen mode
- Replace CSS 100vh with 100% in fullscreen rules
Also includes all v0.3.0 changes (server-side checkpoints, 4:3 aspect ratio fix).