feat: add templates, history, comparison mode, animations, and empty states

- Add text templates with 16 pre-made options across 4 categories (greeting, tech, fun, seasonal)
- Add copy history panel tracking last 10 copied items with restore functionality
- Add font comparison mode to view multiple fonts side-by-side (up to 6 fonts)
- Add smooth animations: slide-down, slide-up, scale-in, fade-in, pulse, and shimmer
- Add loading skeletons for better perceived performance
- Add EmptyState component with contextual messages and icons
- Add hover effects and transitions throughout the UI
- Improve visual feedback with animated badges and shadows

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

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

components/ui/Skeleton.tsx

@@ -0,0 +1,22 @@
+import { cn } from '@/lib/utils/cn';
+
+export interface SkeletonProps extends React.HTMLAttributes<HTMLDivElement> {}
+
+export function Skeleton({ className, ...props }: SkeletonProps) {
+  return (
+    <div
+      className={cn('animate-pulse rounded-md bg-muted', className)}
+      {...props}
+    />
+  );
+}
+
+export function SkeletonText({ className, ...props }: SkeletonProps) {
+  return (
+    <div className={cn('space-y-2', className)} {...props}>
+      <Skeleton className="h-4 w-full" />
+      <Skeleton className="h-4 w-5/6" />
+      <Skeleton className="h-4 w-4/6" />
+    </div>
+  );
+}