feat: Website-Rework mit verbessertem Design, Sicherheit und Deployment

- Neue About/Skills-Sektion hinzugefügt
- Verbesserte UI/UX für alle Komponenten
- Enhanced Contact Form mit Validierung
- Verbesserte Security Headers und Middleware
- Sichere Deployment-Skripte (safe-deploy.sh)
- Zero-Downtime Deployment Support
- Verbesserte Docker-Sicherheit
- Umfassende Sicherheits-Dokumentation
- Performance-Optimierungen
- Accessibility-Verbesserungen

next.config.ts

@@ -42,15 +42,61 @@ const nextConfig: NextConfig = {
   
   // Dynamic routes are handled automatically by Next.js
   
-  // Add cache-busting headers
+  // Security and cache headers
   async headers() {
     return [
       {
         source: '/(.*)',
+        headers: [
+          {
+            key: 'X-DNS-Prefetch-Control',
+            value: 'on',
+          },
+          {
+            key: 'Strict-Transport-Security',
+            value: 'max-age=63072000; includeSubDomains; preload',
+          },
+          {
+            key: 'X-Frame-Options',
+            value: 'DENY',
+          },
+          {
+            key: 'X-Content-Type-Options',
+            value: 'nosniff',
+          },
+          {
+            key: 'X-XSS-Protection',
+            value: '1; mode=block',
+          },
+          {
+            key: 'Referrer-Policy',
+            value: 'strict-origin-when-cross-origin',
+          },
+          {
+            key: 'Permissions-Policy',
+            value: 'camera=(), microphone=(), geolocation=()',
+          },
+          {
+            key: 'Content-Security-Policy',
+            value: "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://analytics.dk0.dev; script-src-elem 'self' 'unsafe-inline' https://analytics.dk0.dev; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; font-src 'self' https://fonts.gstatic.com data:; img-src 'self' data: https:; connect-src 'self' https://analytics.dk0.dev; frame-ancestors 'none'; base-uri 'self'; form-action 'self';",
+          },
+        ],
+      },
+      {
+        source: '/api/(.*)',
         headers: [
           {
             key: 'Cache-Control',
-            value: 'public, max-age=0, must-revalidate',
+            value: 'no-store, no-cache, must-revalidate, proxy-revalidate',
+          },
+        ],
+      },
+      {
+        source: '/_next/static/(.*)',
+        headers: [
+          {
+            key: 'Cache-Control',
+            value: 'public, max-age=31536000, immutable',
           },
         ],
       },