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

routes/web.php

@@ -1,7 +1,9 @@
 <?php
 
 use App\Http\Controllers\ProfileController;
+use App\Http\Controllers\HelpController;
 use App\Http\Controllers\Admin\UserController as AdminUserController;
+use App\Http\Controllers\Admin\LayoutController as AdminLayoutController;
 use Illuminate\Support\Facades\Route;
 
 Route::get('/', function () {
@@ -25,6 +27,18 @@ Route::prefix('admin')
     ->group(function () {
         Route::get('/', fn() => redirect()->route('admin.users.index'));
         Route::resource('users', AdminUserController::class);
+        Route::get('layout', [AdminLayoutController::class, 'index'])->name('layout.index');
+        Route::put('layout', [AdminLayoutController::class, 'update'])->name('layout.update');
+        Route::get('layout/remove-logo', [AdminLayoutController::class, 'removeLogo'])->name('layout.removeLogo');
+    });
+
+// Hilfe-Bereich – für alle eingeloggten Benutzer
+Route::prefix('help')
+    ->name('help.')
+    ->middleware(['auth'])
+    ->group(function () {
+        Route::get('manual', [HelpController::class, 'manual'])->name('manual');
+        Route::get('changelog', [HelpController::class, 'changelog'])->name('changelog');
     });
 
 require __DIR__.'/auth.php';