macos: use xcodeproj

macos/Sources/GhosttyApp.swift

@@ -0,0 +1,13 @@
+import SwiftUI
+import GhosttyKit
+
+@main
+struct GhosttyApp: App {
+    @State private var num = ghostty_hello()
+    
+    var body: some Scene {
+        WindowGroup {
+            Text(String(num)).font(.largeTitle)
+        }
+    }
+}