enhance: save preference.json instantly

[gadfly3173]

No description provided.

[love-linger]

Is there any BUG with preference.json saving?

[gadfly3173]

Is there any BUG with preference.json saving?

Now saving will only be triggered when you manually close the app. If you force shutdown when Windows shutdown, software crashes, etc., preference.json will not be saved, which is sometimes a bit confusing.

[gadfly3173]

The current PR does not save the configuration when the RepositoryNode changes, which should be safe.

[love-linger]

You should solve the problem in this way.

1. Modify App.Initialize() in App.axaml.cs:
   
2. Modify Preference.cs in ViewModels by calling Save() in AddNode(...), MoveNode(...), RemoveNode(...) and SortByRenamedNode(...)

[gadfly3173]

The reason for using asynchronous operations when not closing the application is that File.WriteAllText is a synchronous operation. Frequent calls to it to write files may cause lag in some environments. For example, WSL2 file operations are performed over the network, and the IO performance is very low.

9fe8ffc increased the number of saving opertions for the MoveNode method. When called synchronously and without deduplication, the Save method will be called 3 times in RemoveNode, AddNode, and MoveNode method.

[love-linger]

Yes, I know. As I commented in the commit message, using asynchronous operation will reduce the times calling Save method, but the issue you metioned above still exists since the real saving operation will take place after 3 seconds or even more if there are another change of Preference occurs.