Implement screenshot-based preview system for hub
- Add html2canvas to Vite template for taking screenshots
- Create ScreenshotCapture component that sends screenshots via postMessage
- Update Dev0Panel to listen for screenshot messages and save them
- Add endpoints to save and serve screenshots from daemon
- Replace iframe previews with screenshot thumbnails in hub
- Include screenshot URL in hub project metadata
- Clean up screenshots when projects are deleted
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
