M0: Skelett + Auth-Grundgerüst (Keycloak-OIDC + API-Token)

- Symfony 7.4 LTS, PHP 8.4, FrankenPHP, SQLite (3-Layer src/UI|Logic|Data)
- Auth: manueller OidcClient (Authorization-Code) im UI-Layer, kein
  Security-Bundle/league; Session-Gate via SessionAuthSubscriber
- API-Guard via statischem X-Api-Token (ApiTokenSubscriber); ExceptionSubscriber
- UserEntity (Auto-Provision) + Init-Migration
- Docker (php:8.4-frankenphp) + compose (essen.ljh31.de, traefik-net external)
- SmokeTests (7) grün: Redirect-Fälle, API-Token, Auth-Render, Logout

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/UI/Http/HomeController.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\UI\Http;
+
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+final class HomeController extends AbstractController
+{
+    /**
+     * GET / — Hello-World-Statusseite (M0).
+     */
+    public function index(Request $request, string $redirect = '/'): Response
+    {
+        $session = $request->getSession();
+        $name = (string) $session->get('auth_name', '');
+        $email = (string) $session->get('auth_email', '');
+
+        return $this->render('home/index.html.twig', [
+            'name' => $name,
+            'email' => $email,
+            'redirect' => $redirect === '' ? '/' : $redirect,
+        ]);
+    }
+}