feat: Add professional portfolio images and Hero redesign

- Add 15 optimized WebP images for portfolio (21-53KB each)
- Redesign Hero section with full-width background image
- Add SSR support for Hero component
- Update About section with new portrait image
- Update Contact page with professional headshot
- Add images to Services/Leistungen page
- Add image optimization script (sharp)
- Update translations for gallery section

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app/robots.ts

@@ -0,0 +1,17 @@
+import { MetadataRoute } from 'next';
+
+export default function robots(): MetadataRoute.Robots {
+  const baseUrl = process.env.NEXT_PUBLIC_SITE_URL || 'https://damjan-savic.com';
+
+  return {
+    rules: [
+      {
+        userAgent: '*',
+        allow: '/',
+        disallow: ['/login', '/dashboard', '/api/', '/admin', '/.env'],
+        crawlDelay: 1,
+      },
+    ],
+    sitemap: `${baseUrl}/sitemap.xml`,
+  };
+}