Stand: SMTP-Test, Admin-Mail-Tab, Notifiable-Fix, Lazy-Quill

- Fix: Notifiable-Trait zum User-Model hinzugefuegt (behebt notify()-500er)
- Installer: SMTP-Verbindungstest mit EsmtpTransport + Ueberspringen-Link
- Admin: Neuer E-Mail-Tab mit SMTP-Konfiguration + Verbindungstest
- Admin: Lazy Quill-Initialisierung (nur sichtbare Locale wird geladen)
- Uebersetzungen: 17 neue Mail-Keys in allen 6 Sprachen

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Http/Middleware/SecurityHeadersMiddleware.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Closure;
+use Illuminate\Http\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+class SecurityHeadersMiddleware
+{
+    public function handle(Request $request, Closure $next): Response
+    {
+        $response = $next($request);
+
+        // Server-Fingerprinting verhindern
+        header_remove('X-Powered-By');
+        $response->headers->remove('X-Powered-By');
+        $response->headers->remove('Server');
+
+        // Content Security Policy — erlaubt CDN-Quellen für Tailwind, Alpine, Quill, Leaflet
+        // 'unsafe-inline' benötigt von: Tailwind CDN (inline Styles), Alpine.js (Event-Handler)
+        // 'unsafe-eval' benötigt von: Tailwind CDN (JIT nutzt new Function())
+        // Entfernung nur möglich durch Wechsel auf self-hosted/kompilierte Assets
+        $cspDirectives = [
+            "default-src 'self'",
+            "script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.tailwindcss.com https://cdn.jsdelivr.net https://unpkg.com https://cdn.quilljs.com",
+            "style-src 'self' 'unsafe-inline' https://cdn.tailwindcss.com https://cdn.jsdelivr.net https://unpkg.com https://cdn.quilljs.com",
+            "img-src 'self' data: https://*.tile.openstreetmap.org https://unpkg.com",
+            "font-src 'self' https://cdn.jsdelivr.net https://cdn.quilljs.com",
+            "connect-src 'self' https://photon.komoot.io",
+            "frame-src 'self'",
+            "object-src 'none'",
+            "base-uri 'self'",
+            "form-action 'self'",
+        ];
+
+        // upgrade-insecure-requests nur bei HTTPS — bricht sonst lokale HTTP-Entwicklung (Herd/artisan serve)
+        if ($request->secure()) {
+            $cspDirectives[] = "upgrade-insecure-requests";
+        }
+
+        $csp = implode('; ', $cspDirectives);
+
+        $response->headers->set('Content-Security-Policy', $csp);
+        $response->headers->set('X-Content-Type-Options', 'nosniff');
+        $response->headers->set('X-Frame-Options', 'SAMEORIGIN');
+        $response->headers->set('X-XSS-Protection', '1; mode=block');
+        $response->headers->set('Referrer-Policy', 'strict-origin-when-cross-origin');
+        $response->headers->set('Permissions-Policy', 'camera=(), microphone=(), geolocation=(self), payment=(), usb=(), bluetooth=(), autoplay=(), magnetometer=(), gyroscope=(), accelerometer=()');
+
+        // Cross-Origin Isolation Headers
+        $response->headers->set('Cross-Origin-Opener-Policy', 'same-origin-allow-popups');
+
+        // HSTS — HTTPS fuer 1 Jahr erzwingen (nur bei HTTPS-Requests aktiv)
+        if ($request->secure()) {
+            $response->headers->set('Strict-Transport-Security', 'max-age=31536000; includeSubDomains');
+        }
+
+        return $response;
+    }
+}