feat(config, layout, components): enhance security headers, improve SEO, and update project descriptions

- Added security headers in the Next.js configuration to enhance application security.
- Updated metadata in the layout component for improved SEO, including new titles, descriptions, and keywords.
- Introduced JSON-LD schema for projects to enhance search engine visibility.
- Enhanced project descriptions in the portfolio data for clarity and detail.
- Improved header component with logo integration and refined social media links for better accessibility.

app/not-found.tsx

@@ -0,0 +1,38 @@
+import Link from "next/link";
+import { Home, ArrowLeft, Code2 } from "lucide-react";
+
+export default function NotFound() {
+  return (
+    <div className="min-h-screen bg-[#030712] flex items-center justify-center px-6">
+      <div className="max-w-2xl mx-auto text-center">
+        <div className="mb-8">
+          <Code2 className="w-24 h-24 text-blue-500 mx-auto mb-4 opacity-50" />
+          <h1 className="text-6xl md:text-8xl font-black text-white mb-4">404</h1>
+          <h2 className="text-2xl md:text-3xl font-bold text-slate-400 mb-4">
+            Página não encontrada
+          </h2>
+          <p className="text-slate-500 mb-8">
+            A página que você está procurando não existe ou foi movida.
+          </p>
+        </div>
+        
+        <div className="flex flex-col sm:flex-row gap-4 justify-center">
+          <Link
+            href="/"
+            className="px-6 py-3 bg-blue-600 hover:bg-blue-500 text-white rounded-lg font-semibold transition-all flex items-center justify-center gap-2"
+          >
+            <Home className="w-5 h-5" />
+            Voltar para Home
+          </Link>
+          <Link
+            href="/#projects"
+            className="px-6 py-3 border border-slate-800 hover:border-slate-600 text-slate-400 hover:text-white rounded-lg font-semibold transition-all flex items-center justify-center gap-2"
+          >
+            <ArrowLeft className="w-5 h-5" />
+            Ver Projetos
+          </Link>
+        </div>
+      </div>
+    </div>
+  );
+}