Implement asynchronous save manager with UI update optimizations and add tests for save functionality

ui/actions/actions.gd

@@ -47,7 +47,9 @@ func _set_action_values(values: Array, displayed: Array) -> void:
     for ind in range(0, 5):
         action_values[ind] = values[ind]
         # Keep the original request for execution; show the exact planned output.
-        action_labels[ind].text = Global.format_number(displayed[ind]) if displayed[ind] > 0 else ""
+        var text: String = Global.format_number(displayed[ind]) if displayed[ind] > 0 else ""
+        if action_labels[ind].text != text:
+            action_labels[ind].text = text
         
 
 func _on_action_button_pressed(button_id: int) -> void:

ui/owniverse_item/owniverse_item.gd

@@ -20,7 +20,9 @@ var item_type = ""
 
 
 func set_label(value: float) -> void:
-    description.text = Global.format_number(value)
+    var text: String = Global.format_number(value)
+    if description.text != text:
+        description.text = text
     #description.text = str(value)