Add RollkofferSimulator iOS SpriteKit arcade game

Complete implementation of a 2D top-down arcade collector game where players
control a rolling suitcase through an airport, collecting good dogs and green
people while avoiding bad dogs and gray people.

Features:
- Touch & drag controls for suitcase movement
- Automatic scrolling airport floor with tile pattern
- 4 entity types: good dogs (small/big), bad dogs, green/gray humans
- Spawn system with configurable distribution rates
- Collision detection with visual feedback effects
- Score tracking with high score persistence
- 90-second time limit with 10 dogs + 5 humans goal
- 3 lives system with invincibility frames
- Menu, Game, GameOver, and Victory scenes
- German UI text (Created by Ingo K.)

Technical:
- iOS 15+ with SpriteKit framework
- Modular architecture with Nodes, Managers, Scenes
- Physics-based collision detection
- UserDefaults for score persistence

RollkofferSimulator/AppDelegate.swift

@@ -0,0 +1,42 @@
+//
+//  AppDelegate.swift
+//  RollkofferSimulator
+//
+//  Created by Ingo K.
+//
+
+import UIKit
+
+@main
+class AppDelegate: UIResponder, UIApplicationDelegate {
+
+    var window: UIWindow?
+
+    func application(_ application: UIApplication,
+                     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
+        return true
+    }
+
+    func applicationWillResignActive(_ application: UIApplication) {
+        // Pause the game when app goes to background
+        NotificationCenter.default.post(name: .pauseGame, object: nil)
+    }
+
+    func applicationDidEnterBackground(_ application: UIApplication) {
+        // Save game state if needed
+    }
+
+    func applicationWillEnterForeground(_ application: UIApplication) {
+        // Restore game state if needed
+    }
+
+    func applicationDidBecomeActive(_ application: UIApplication) {
+        // Resume game if needed
+    }
+}
+
+// MARK: - Notification Names
+extension Notification.Name {
+    static let pauseGame = Notification.Name("pauseGame")
+    static let resumeGame = Notification.Name("resumeGame")
+}