Migrate from Vite to Next.js 15 with SSR

- Replace Vite + React Router with Next.js 15 App Router
- Implement i18n with next-intl (URL-based: /de, /en, /sr)
- Add SSR/SSG for all pages (48 static pages generated)
- Setup Supabase SSR client for auth
- Migrate all pages: Home, About, Portfolio, Blog, Contact, Login, Dashboard, Imprint, Privacy, Terms
- Add Docker support with standalone output
- Replace i18next with next-intl JSON translations
- Use next/image for optimized images

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

src/components-vite/SkeletonLoader.tsx

@@ -0,0 +1,52 @@
+import React from 'react';
+
+interface SkeletonProps {
+  className?: string;
+}
+
+const Skeleton: React.FC<SkeletonProps> = ({ className }) => (
+  <div className={`animate-pulse bg-gray-700/50 rounded ${className}`}></div>
+);
+
+export const BlogPostSkeleton = () => (
+  <div className="max-w-4xl mx-auto px-4 sm:px-6 lg:px-8 py-24">
+    <Skeleton className="h-8 w-3/4 mb-4" />
+    <Skeleton className="h-4 w-1/4 mb-8" />
+    <Skeleton className="h-[400px] w-full mb-8 rounded-xl" />
+    <div className="space-y-4">
+      <Skeleton className="h-4 w-full" />
+      <Skeleton className="h-4 w-5/6" />
+      <Skeleton className="h-4 w-4/6" />
+    </div>
+  </div>
+);
+
+export const ProjectSkeleton = () => (
+  <div className="max-w-4xl mx-auto px-4 sm:px-6 lg:px-8 py-24">
+    <Skeleton className="h-8 w-2/3 mb-4" />
+    <div className="flex gap-4 mb-8">
+      <Skeleton className="h-4 w-24" />
+      <Skeleton className="h-4 w-24" />
+      <Skeleton className="h-4 w-24" />
+    </div>
+    <Skeleton className="h-[400px] w-full mb-8 rounded-xl" />
+    <div className="space-y-4">
+      <Skeleton className="h-4 w-full" />
+      <Skeleton className="h-4 w-5/6" />
+      <Skeleton className="h-4 w-4/6" />
+    </div>
+  </div>
+);
+
+export const PortfolioSkeleton = () => (
+  <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-24">
+    <Skeleton className="h-8 w-48 mx-auto mb-12" />
+    <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-8">
+      {[1, 2, 3].map((i) => (
+        <div key={i} className="aspect-[4/3]">
+          <Skeleton className="w-full h-full rounded-xl" />
+        </div>
+      ))}
+    </div>
+  </div>
+);