chore: projekt-scaffold mit next 15, tailwind und shadcn/ui

Next.js 15 (App Router, TypeScript strict), Tailwind CSS 4 und
shadcn/ui als Basis. Standalone-Output und serverExternalPackages
sind fuer den spaeteren Docker-Build vorbereitet.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tsconfig.json

@@ -0,0 +1,27 @@
+{
+  "compilerOptions": {
+    "target": "ES2017",
+    "lib": ["dom", "dom.iterable", "esnext"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "preserve",
+    "incremental": true,
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ],
+    "paths": {
+      "@/*": ["./src/*"]
+    }
+  },
+  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
+  "exclude": ["node_modules"]
+}