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/Controllers/Admin/FileCategoryController.php

@@ -0,0 +1,64 @@
+<?php
+
+namespace App\Http\Controllers\Admin;
+
+use App\Http\Controllers\Controller;
+use App\Models\FileCategory;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+use Illuminate\Support\Str;
+
+class FileCategoryController extends Controller
+{
+    public function store(Request $request): RedirectResponse
+    {
+        $request->validate([
+            'name' => ['required', 'string', 'max:255'],
+        ]);
+
+        $slug = Str::slug($request->name);
+
+        // Ensure unique slug
+        $originalSlug = $slug;
+        $counter = 1;
+        while (FileCategory::where('slug', $slug)->exists()) {
+            $slug = $originalSlug . '-' . $counter++;
+        }
+
+        $maxOrder = FileCategory::max('sort_order') ?? 0;
+
+        FileCategory::create([
+            'name' => $request->name,
+            'slug' => $slug,
+            'sort_order' => $maxOrder + 1,
+        ]);
+
+        return back()->with('success', __('admin.category_created'));
+    }
+
+    public function update(Request $request, FileCategory $category): RedirectResponse
+    {
+        $request->validate([
+            'name' => ['required', 'string', 'max:255'],
+            'is_active' => ['nullable', 'boolean'],
+        ]);
+
+        $category->update([
+            'name' => $request->name,
+            'is_active' => $request->boolean('is_active'),
+        ]);
+
+        return back()->with('success', __('admin.category_updated'));
+    }
+
+    public function destroy(FileCategory $category): RedirectResponse
+    {
+        if ($category->files()->exists()) {
+            return back()->with('error', __('admin.category_not_empty'));
+        }
+
+        $category->delete();
+
+        return back()->with('success', __('admin.category_deleted'));
+    }
+}