feat(perf,ux): implement performance and UX optimizations

Phase 2: Performance Optimizations
- Implement dynamic imports for non-critical sections
- Add loading skeletons for lazy-loaded components
- Optimize bundle size with code splitting
- Enable SSR for dynamic components

Phase 3: UX Optimizations
- Create ErrorBoundary component for graceful error handling
- Add Toast notification component for user feedback
- Implement success/error notifications in contact form
- Add error handling with user-friendly messages

Files modified:
- src/app/(marketing)/page.tsx: Dynamic imports for sections
- src/app/(marketing)/layout.tsx: Error boundary integration
- src/components/sections/contact-section.tsx: Toast notifications
- src/components/ui/error-boundary.tsx: New error boundary component
- src/components/ui/toast.tsx: New toast notification component

Impact:
- Reduced initial bundle size
- Faster page load times
- Better error handling
- Improved user feedback
- Enhanced user experience

src/app/(marketing)/layout.tsx

@@ -1,3 +1,5 @@
+import { ErrorBoundary } from '@/components/ui/error-boundary';
+
 export default function MarketingLayout({
   children,
 }: {
@@ -5,7 +7,9 @@ export default function MarketingLayout({
 }) {
   return (
     <div className="min-h-screen flex flex-col">
-      <main className="flex-1">{children}</main>
+      <ErrorBoundary>
+        <main className="flex-1">{children}</main>
+      </ErrorBoundary>
     </div>
   );
 }