Refactor landing page layout and update assets

- Replaced the Hero component with a new section layout for improved structure and responsiveness.
- Updated download buttons for macOS, Windows, and Linux with enhanced styling.
- Added a new application screenshot in WebP format and removed the old App.webp asset.
- Adjusted Header component to capitalize the application name for consistency.
- Minor formatting improvements in HistoryTable for better readability.

landing/src/components/Header.tsx

@@ -1,7 +1,7 @@
 'use client';
 
-import Link from 'next/link';
 import { Github } from 'lucide-react';
+import Link from 'next/link';
 import { Button } from '@/components/ui/button';
 import { GITHUB_REPO } from '@/lib/constants';
 
@@ -15,7 +15,7 @@ export function Header() {
             href="/"
             className="flex items-center gap-2 font-bold text-xl sm:text-2xl hover:opacity-80 transition-opacity tracking-tight"
           >
-            voicebox
+            Voicebox
           </Link>
 
           {/* Actions */}