Started 128K model

Core/SpectrumMachine.cs

@@ -9,8 +9,14 @@ using System.Threading.Tasks;
 
 namespace Core
 {
+    public enum MachineModel
+    {
+        Spectrum48K,
+        SpectrumPlus2A
+    }
     public class SpectrumMachine
     {
+        public MachineModel CurrentModel { get; private set; } = MachineModel.Spectrum48K;
         // The Hardware
         public Z80 Cpu { get; private set; }
         public MemoryBus Memory { get; private set; }
@@ -43,6 +49,15 @@ namespace Core
         public event Action<double, bool>? OnStatsUpdated; // Passes FPS and TapeLoaded status
         public event Action<string>? OnMachineCrashed;
 
+        public void SetMachineModel(MachineModel newModel)
+        {
+            if (CurrentModel == newModel) return; // Do nothing if it's the same
+
+            CurrentModel = newModel;
+
+            // Flag the main loop to perform a hard reset on the next frame
+            _pendingReset = true;
+        }
         public SpectrumMachine(IAudioDevice beeperDevice)
         {
             _beeper = beeperDevice;