Refactor SecurityPrivacySettings component

Refactor the SecurityPrivacySettings component into smaller, more manageable sub-components for improved readability and maintainability. The functionality of the page remains unchanged.

src/components/security/SecurityHeader.tsx

@@ -0,0 +1,27 @@
+
+import React from 'react';
+import { ArrowLeft } from 'lucide-react';
+import { useNavigate } from 'react-router-dom';
+import { Button } from '@/components/ui/button';
+
+const SecurityHeader = () => {
+  const navigate = useNavigate();
+  
+  return (
+    <header className="py-8">
+      <div className="flex items-center mb-6">
+        <Button 
+          variant="ghost" 
+          size="icon" 
+          onClick={() => navigate('/settings')}
+          className="mr-2"
+        >
+          <ArrowLeft size={20} />
+        </Button>
+        <h1 className="text-2xl font-bold neuro-text">보안 및 개인정보</h1>
+      </div>
+    </header>
+  );
+};
+
+export default SecurityHeader;