feat.在线安装器，更好的Issue与pull request模板。

LanDesktopPLONDS.installer/Views/MainWindow.axaml.cs

@@ -0,0 +1,62 @@
+using Avalonia.Controls;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.Platform.Storage;
+using LanDesktopPLONDS.Installer.ViewModels;
+
+namespace LanDesktopPLONDS.Installer.Views;
+
+public partial class MainWindow : Window
+{
+    public MainWindow()
+    {
+        InitializeComponent();
+    }
+
+    protected override void OnDataContextChanged(EventArgs e)
+    {
+        base.OnDataContextChanged(e);
+        if (DataContext is MainWindowViewModel viewModel)
+        {
+            viewModel.BrowseRequested = BrowseForFolderAsync;
+        }
+    }
+
+    private async Task<string?> BrowseForFolderAsync(string currentPath)
+    {
+        var startFolder = Directory.Exists(currentPath)
+            ? await StorageProvider.TryGetFolderFromPathAsync(currentPath)
+            : null;
+        var result = await StorageProvider.OpenFolderPickerAsync(new FolderPickerOpenOptions
+        {
+            Title = "选择安装位置",
+            AllowMultiple = false,
+            SuggestedStartLocation = startFolder
+        });
+
+        return result.Count == 0 ? null : result[0].Path.LocalPath;
+    }
+
+    private void OnTitleBarPointerPressed(object? sender, PointerPressedEventArgs e)
+    {
+        _ = sender;
+        if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
+        {
+            BeginMoveDrag(e);
+        }
+    }
+
+    private void OnMinimizeClick(object? sender, RoutedEventArgs e)
+    {
+        _ = sender;
+        _ = e;
+        WindowState = WindowState.Minimized;
+    }
+
+    private void OnCloseClick(object? sender, RoutedEventArgs e)
+    {
+        _ = sender;
+        _ = e;
+        Close();
+    }
+}