feat: initialize Convert UI - browser-based file conversion app

- Add Next.js 16 with Turbopack and React 19
- Add Tailwind CSS 4 with OKLCH color system
- Implement FFmpeg.wasm for video/audio conversion
- Implement ImageMagick WASM for image conversion
- Add file upload with drag-and-drop
- Add format selector with fuzzy search
- Add conversion preview and download
- Add conversion history with localStorage
- Add dark/light theme support
- Support 22+ file formats across video, audio, and images

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

lib/utils/debounce.ts

@@ -0,0 +1,21 @@
+/**
+ * Debounce function - delays execution until after wait time has elapsed
+ */
+export function debounce<T extends (...args: any[]) => any>(
+  func: T,
+  wait: number
+): (...args: Parameters<T>) => void {
+  let timeout: NodeJS.Timeout | null = null;
+
+  return function executedFunction(...args: Parameters<T>) {
+    const later = () => {
+      timeout = null;
+      func(...args);
+    };
+
+    if (timeout) {
+      clearTimeout(timeout);
+    }
+    timeout = setTimeout(later, wait);
+  };
+}