feat(layout): Layout-Einstellungen, Dark-Mode, Logo, Hilfe-Menü

- Settings Key-Value Store (DB + Cache)
- Einstellungen → Layout: Seitenname, Logo, Button-Farbe, Dark/Light-Mode
- Hilfe-Menü (Ebene 0): Handbuch + Changelog im Browser
- Navigation erweitert: Einstellungen-Dropdown + Hilfe-Dropdown
- CHANGELOG v0.4.0

Version: 0.4.0

app/Http/Controllers/Admin/LayoutController.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace App\Http\Controllers\Admin;
+
+use App\Http\Controllers\Controller;
+use App\Services\SettingsService;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+use Illuminate\View\View;
+
+class LayoutController extends Controller
+{
+    public function __construct(private SettingsService $settings) {}
+
+    public function index(): View
+    {
+        return view('admin.layout.index', [
+            'settings' => $this->settings->all(),
+        ]);
+    }
+
+    public function update(Request $request): RedirectResponse
+    {
+        $validated = $request->validate([
+            'site_name'    => ['required', 'string', 'max:100'],
+            'button_color' => ['required', 'string', 'regex:/^#[0-9a-fA-F]{6}$/'],
+            'theme_mode'   => ['required', 'in:light,dark'],
+            'site_logo'    => ['nullable', 'image', 'max:2048'],
+        ]);
+
+        // Logo-Upload verarbeiten
+        if ($request->hasFile('site_logo')) {
+            $path = $request->file('site_logo')->store('logos', 'public');
+            $this->settings->set('site_logo', $path);
+        }
+
+        $this->settings->setMany([
+            'site_name'    => $validated['site_name'],
+            'button_color' => $validated['button_color'],
+            'theme_mode'   => $validated['theme_mode'],
+        ]);
+
+        return redirect()
+            ->route('admin.layout.index')
+            ->with('success', 'Layout-Einstellungen gespeichert.');
+    }
+
+    public function removeLogo(): RedirectResponse
+    {
+        $this->settings->set('site_logo', '');
+
+        return redirect()
+            ->route('admin.layout.index')
+            ->with('success', 'Logo entfernt.');
+    }
+}

app/Http/Controllers/Admin/UserController.php

@@ -47,7 +47,7 @@ class UserController extends Controller
 
         return redirect()
             ->route('admin.users.index')
-            ->with('success', "Benutzer „{$user->name}" wurde angelegt.");
+            ->with('success', "Benutzer \"{$user->name}\" wurde angelegt.");
     }
 
     public function edit(User $user): View
@@ -79,7 +79,7 @@ class UserController extends Controller
 
         return redirect()
             ->route('admin.users.index')
-            ->with('success', "Benutzer „{$user->name}" wurde aktualisiert.");
+            ->with('success', "Benutzer \"{$user->name}\" wurde aktualisiert.");
     }
 
     public function destroy(User $user): RedirectResponse
@@ -95,6 +95,6 @@ class UserController extends Controller
 
         return redirect()
             ->route('admin.users.index')
-            ->with('success', "Benutzer „{$name}" wurde gelöscht.");
+            ->with('success', "Benutzer \"{$name}\" wurde gelöscht.");
     }
 }