macos: starting boilerplate

macos/Sources/Ghostty/main.swift

@@ -0,0 +1,23 @@
+import SwiftUI
+
+@main
+struct Ghostty: App {
+  var body: some Scene {
+    WindowGroup {
+      ContentView()
+    }
+  }
+}
+
+struct ContentView: View {
+  @StateObject var viewModel: ViewModel  = ViewModel()
+
+  var body: some View {
+    TextField("", text: $viewModel.inputText)
+      .padding()
+  }
+}
+
+public class ViewModel: ObservableObject {
+  @Published var inputText: String = ""
+}