feat: implement dark mode infrastructure, optimize images, and add SEO structured data

app/components/Header.tsx

@@ -7,6 +7,7 @@ import { SiGithub, SiLinkedin } from "react-icons/si";
 import Link from "next/link";
 import { useLocale, useTranslations } from "next-intl";
 import { usePathname, useSearchParams } from "next/navigation";
+import { ThemeToggle } from "./ThemeToggle";
 
 const Header = () => {
   const [isOpen, setIsOpen] = useState(false);
@@ -155,6 +156,7 @@ const Header = () => {
                   DE
                 </Link>
               </div>
+              <ThemeToggle />
               {socialLinks.map((social) => (
                 <motion.a
                   key={social.label}
@@ -233,7 +235,8 @@ const Header = () => {
                   ))}
 
                   <div className="pt-6 mt-4 border-t border-stone-200">
-                    <div className="flex justify-center space-x-4">
+                    <div className="flex justify-center items-center space-x-4">
+                      <ThemeToggle />
                       {socialLinks.map((social, index) => (
                         <motion.a
                           key={social.label}