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/PageContainer.tsx

@@ -0,0 +1,20 @@
+// components/PageContainer.tsx
+import React, { Suspense } from 'react';
+
+interface PageContainerProps {
+    children: React.ReactNode;
+}
+
+const PageContainer = ({ children }: PageContainerProps) => {
+    return (
+        <div className="flex flex-col min-h-screen">
+            <Suspense fallback={null}>
+                <main className="flex-1 pt-16">
+                    {children}
+                </main>
+            </Suspense>
+        </div>
+    );
+};
+
+export default PageContainer;