Optimize bundle size and implement code splitting

Description

The web-app-react bundle size is too large (5.2MB), causing slow initial load times.

Current Metrics

• Bundle size: 5.2MB
• First Contentful Paint: 4.2s
• Time to Interactive: 6.8s

Tasks

• Implement React.lazy() for route-based code splitting
• Analyze bundle with webpack-bundle-analyzer
• Remove unused dependencies
• Optimize images and assets
• Implement dynamic imports for heavy components

Target Metrics

• Bundle size: <1MB (main chunk)
• FCP: <2s
• TTI: <3.5s

cc @jean @michael