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

resources/views/admin/users/index.blade.php

@@ -1,19 +1,21 @@
 <x-app-layout>
     <x-slot name="header">
-        <div class="flex items-center justify-between">
-            <h2 class="font-semibold text-xl text-gray-800 leading-tight">
-                Benutzerverwaltung
-            </h2>
-            <a href="{{ route('admin.users.create') }}"
-               class="inline-flex items-center px-4 py-2 bg-indigo-600 text-white text-sm font-medium rounded-md hover:bg-indigo-700 transition">
-                + Neuer Benutzer
-            </a>
-        </div>
+        <h2 class="font-semibold text-xl text-gray-800 leading-tight">
+            Benutzerverwaltung
+        </h2>
     </x-slot>
 
     <div class="py-12">
         <div class="max-w-7xl mx-auto sm:px-6 lg:px-8">
 
+            {{-- Toolbar --}}
+            <div class="flex justify-end mb-4">
+                <a href="{{ route('admin.users.create') }}"
+                   class="inline-flex items-center px-4 py-2 bg-indigo-600 text-white text-sm font-medium rounded-md hover:bg-indigo-700 transition">
+                    + Neuer Benutzer
+                </a>
+            </div>
+
             {{-- Flash-Meldungen --}}
             @if(session('success'))
                 <div class="mb-4 p-4 bg-green-100 text-green-800 rounded-md">