fix: add missing Sparkles import in Header.jsx

src/components/Header.jsx

@@ -1,6 +1,6 @@
 import React, { useState } from 'react';
 import { useApp } from '../context/AppContext';
-import { Bot, Search, SlidersHorizontal, Gift, Bell, User, ChevronDown, CheckCircle, LogOut, Globe } from 'lucide-react';
+import { Bot, Search, SlidersHorizontal, Gift, Bell, User, ChevronDown, CheckCircle, LogOut, Globe, Sparkles } from 'lucide-react';
 
 export const Header = () => {
   const {