Implemented a load of Z80 OpCodes. Added SimpleIOBus.

Core/Io/SimpleIoBus.cs

@@ -0,0 +1,20 @@
+using System.Diagnostics;
+using Core.Interfaces;
+
+namespace Core.Io
+{
+    public class SimpleIoBus : IIoBus
+    {
+        public byte Read(ushort port)
+        {
+            // If the CPU reads an unconnected port, the Z80 usually sees 0xFF
+            return 0xFF;
+        }
+
+        public void Write(ushort port, byte value)
+        {
+            // For now, let's just log it to the Visual Studio Output window
+            Debug.WriteLine($"Hardware I/O Write -> Port: 0x{port:X4}, Value: 0x{value:X2}");
+        }
+    }
+}