feat: implement Figlet, Pastel, and Unit tools with a unified layout

- Add Figlet text converter with font selection and history
- Add Pastel color palette generator and manipulation suite
- Add comprehensive Units converter with category-based logic
- Introduce AppShell with Sidebar and Header for navigation
- Modernize theme system with CSS variables and new animations
- Update project configuration and dependencies

components/ui/Input.tsx

@@ -0,0 +1,28 @@
+import * as React from 'react';
+import { cn } from '@/lib/utils/cn';
+
+export interface InputProps extends React.InputHTMLAttributes<HTMLInputElement> {}
+
+const Input = React.forwardRef<HTMLInputElement, InputProps>(
+  ({ className, type, ...props }, ref) => {
+    return (
+      <input
+        type={type}
+        className={cn(
+          'flex h-10 w-full rounded-xl border border-white/10 bg-white/5 px-4 py-2',
+          'text-sm ring-offset-background file:border-0 file:bg-transparent',
+          'file:text-sm file:font-medium placeholder:text-muted-foreground',
+          'focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary/50 focus-visible:border-primary/50',
+          'disabled:cursor-not-allowed disabled:opacity-50 transition-all duration-200',
+          className
+        )}
+        ref={ref}
+        {...props}
+      />
+    );
+  }
+);
+
+Input.displayName = 'Input';
+
+export { Input };