Frontend: Add performance optimizations (memoization, code splitting)

## Description

Frontend lacks performance optimizations like React.memo, useMemo, useCallback, and code splitting. Large components re-render unnecessarily.

## Current Issues

- No React.memo for expensive components
- Missing useMemo for computed values
- Missing useCallback for event handlers
- No code splitting for routes
- Large bundle size

## Expected Solution

- Add React.memo to expensive components
- Use useMemo for computed values
- Use useCallback for event handlers passed as props
- Implement route-based code splitting
- Analyze bundle size and optimize imports
- Lazy load heavy components

## Benefits

- Faster page loads
- Better user experience
- Reduced re-renders
- Smaller bundle size
- Better Core Web Vitals scores

The issue names no files, tests, or entry points. Start by locating the expensive React components, route configuration, and bundle-analysis tooling, then establish measurements for re-renders, bundle size, and page loading. Done means the requested memoization, route splitting, lazy loading, and import optimizations are implemented and their performance impact is verified.

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