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/MDXProvider.tsx

@@ -0,0 +1,28 @@
+// src/components/MDXProvider.tsx
+import React from 'react';
+import { MDXProvider } from '@mdx-js/react';
+
+const components = {
+    h1: (props: React.ComponentProps<'h1'>) => (
+        <h1 className="text-3xl font-bold my-6" {...props} />
+    ),
+    h2: (props: React.ComponentProps<'h2'>) => (
+        <h2 className="text-2xl font-bold my-4" {...props} />
+    ),
+    h3: (props: React.ComponentProps<'h3'>) => (
+        <h3 className="text-xl font-bold my-3" {...props} />
+    ),
+    p: (props: React.ComponentProps<'p'>) => (
+        <p className="my-4 text-muted-foreground" {...props} />
+    ),
+    code: (props: React.ComponentProps<'code'>) => (
+        <code className="bg-muted px-1.5 py-0.5 rounded text-sm" {...props} />
+    ),
+    pre: (props: React.ComponentProps<'pre'>) => (
+        <pre className="bg-muted p-4 rounded-lg my-4 overflow-x-auto" {...props} />
+    ),
+};
+
+export function MDXLayout({ children }: { children: React.ReactNode }) {
+    return <MDXProvider components={components}>{children}</MDXProvider>;
+}