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/DebugOverlay.tsx

@@ -0,0 +1,41 @@
+import React, { useState, useEffect } from 'react';
+import { useScrollContext } from './ScrollContext';
+
+interface KeyboardEvent {
+    key: string;
+}
+
+const DebugOverlay: React.FC = () => {
+    const [showDebug, setShowDebug] = useState<boolean>(false);
+    const { isTransitioning } = useScrollContext();
+
+    useEffect(() => {
+        const handleKeyPress = (e: KeyboardEvent) => {
+            if (e.key === 'd') {
+                setShowDebug((prev: boolean) => !prev);
+            }
+        };
+
+        window.addEventListener('keydown', handleKeyPress);
+        return () => window.removeEventListener('keydown', handleKeyPress);
+    }, []);
+
+    if (!showDebug) return null;
+
+    return (
+        <div className="fixed bottom-4 right-4 bg-black/80 text-white p-4 rounded-lg z-[100] font-mono text-sm">
+            <div>Transitioning: {isTransitioning ? 'Yes' : 'No'}</div>
+            <div>Body Overflow: {document.body.style.overflow}</div>
+            <div>Scroll Position: {window.scrollY}</div>
+            <div>View Height: {window.innerHeight}</div>
+            <button
+                onClick={() => document.body.style.overflow = ''}
+                className="bg-blue-500 px-2 py-1 rounded mt-2"
+            >
+                Reset Overflow
+            </button>
+        </div>
+    );
+};
+
+export default DebugOverlay;