Add OS-specific interop

Source/LoadByOS/MacOSConfigApp/MacOSInterop.cs

@@ -0,0 +1,28 @@
+using AppScaffolding.OSInterop;
+
+namespace MacOSConfigApp
+{
+    internal class MacOSInterop : IInteropFunctions
+    {
+        public MacOSInterop() { }
+        public MacOSInterop(params object[] values) { }
+
+
+        // examples until the real interface is filled out
+        private string InitValue1 { get; }
+        private int InitValue2 { get; }
+
+        public MacOSInterop(string initValue1, int initValue2)
+        {
+            InitValue1 = initValue1;
+            InitValue2 = initValue2;
+        }
+
+        public string TransformInit1() => InitValue1.ToLower();
+
+        public int TransformInit2() => InitValue2 + InitValue2;
+
+        public void CopyTextToClipboard(string text) => throw new PlatformNotSupportedException();
+        public void ShowForm() => throw new PlatformNotSupportedException();
+    }
+}