SwiftOCAUI: fix tab-between-fields requiring double tab

Defer state updates in commitEdit() to the next run loop iteration
so that SwiftUI completes the focus transfer before re-rendering.

Author: lhoward

Sources/SwiftOCAUI/Views/PropertyView.swift

@@ -200,10 +200,10 @@ public struct OcaWritableTextPropertyView: View {
 
   private func commitEdit() {
     guard let editingValue else { return }
-    currentValue = .success(editingValue)
     let value = editingValue
-    self.editingValue = nil
-    Task {
+    Task { @MainActor in
+      currentValue = .success(value)
+      self.editingValue = nil
       try? await property._setValue(object, value)
     }
   }