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>

tailwind.config.js

@@ -2,11 +2,9 @@
 module.exports = {
   darkMode: ["class"],
   content: [
-    "app/**/*.{ts,tsx}",
-    "components/**/*.{ts,tsx}",
-    "./index.html",
-    "./src/**/*.{js,ts,jsx,tsx}",
-    "*.{js,ts,jsx,tsx,mdx}",
+    "./src/app/**/*.{js,ts,jsx,tsx,mdx}",
+    "./src/components/**/*.{js,ts,jsx,tsx,mdx}",
+    "./src/**/*.{js,ts,jsx,tsx,mdx}",
   ],
   theme: {
     extend: {