fix: open folder pickers at current paths

tests/MBN_STOCK_WEBVIEW.LegacyWeb.Tests/LegacyOperatorSettingsNativeContractTests.cs

@@ -11,26 +11,85 @@ public sealed class LegacyOperatorSettingsNativeContractTests
         Path.Combine(AppRoot, "MainWindow.xaml.cs"));
     private static readonly string Settings = File.ReadAllText(
         Path.Combine(AppRoot, "MainWindow.Settings.cs"));
+    private static readonly string FolderPicker = File.ReadAllText(
+        Path.Combine(AppRoot, "MainWindow.BackgroundPicker.cs"));
     private static readonly string Playout = File.ReadAllText(
         Path.Combine(AppRoot, "MainWindow.Playout.cs"));
 
     [Fact]
     public void FolderPathsComeOnlyFromTheWindowOwnedNativePicker()
     {
-        Assert.Contains("var picker = new FolderPicker", Settings, StringComparison.Ordinal);
-        Assert.Contains("picker.FileTypeFilter.Add(\"*\")", Settings,
+        Assert.Contains(
+            "var initialDirectory = ResolveOperatorFolderPickerStartDirectory(kind)",
+            Settings,
             StringComparison.Ordinal);
-        Assert.Contains("InitializeWithWindow.Initialize(picker, owner);", Settings,
+        Assert.Contains("await PickOperatorFolderAsync(", Settings,
             StringComparison.Ordinal);
-        Assert.Contains("await picker.PickSingleFolderAsync()", Settings,
+        Assert.Contains("LegacyFileDialog.ShowFolder(", FolderPicker,
             StringComparison.Ordinal);
-        Assert.Contains("selected.Path", Settings, StringComparison.Ordinal);
+        Assert.Contains("WindowNative.GetWindowHandle(this)", FolderPicker,
+            StringComparison.Ordinal);
+        Assert.Contains("FileOpenOptions.PickFolders", FolderPicker,
+            StringComparison.Ordinal);
+        Assert.Contains("FileOpenOptions.ForceFileSystem", FolderPicker,
+            StringComparison.Ordinal);
+        Assert.Contains("FileOpenOptions.PathMustExist", FolderPicker,
+            StringComparison.Ordinal);
+        Assert.Contains("FileOpenOptions.NoDereferenceLinks", FolderPicker,
+            StringComparison.Ordinal);
+        Assert.Contains("dialog.SetFolder(initialFolder);", FolderPicker,
+            StringComparison.Ordinal);
+        Assert.Contains("dialog.SetDefaultFolder(initialFolder);", FolderPicker,
+            StringComparison.Ordinal);
+        Assert.Contains("selectedPath", Settings, StringComparison.Ordinal);
         Assert.Contains("LegacyOperatorFolderValidator.TryValidate(", Settings,
             StringComparison.Ordinal);
+        Assert.DoesNotContain("PickerLocationId.ComputerFolder", Settings,
+            StringComparison.Ordinal);
         Assert.DoesNotContain("intent.Path", Settings, StringComparison.Ordinal);
         Assert.DoesNotContain("choose.Path", Settings, StringComparison.Ordinal);
     }
 
+    [Fact]
+    public void FolderPickerStartsAtTheLatestSavedPathOrItsNearestExistingParent()
+    {
+        var resolver = Slice(
+            Settings,
+            "private string? ResolveOperatorFolderPickerStartDirectory(",
+            "private static string ResolveOperatorFolderPickerTitle(");
+
+        Assert.Contains("_operatorSettings.SceneDirectory", resolver,
+            StringComparison.Ordinal);
+        Assert.Contains("_operatorSettings.ResourceDirectory", resolver,
+            StringComparison.Ordinal);
+        Assert.Contains("_operatorSettings.BackgroundDirectory", resolver,
+            StringComparison.Ordinal);
+        Assert.DoesNotContain("_appliedOperatorSettings", resolver,
+            StringComparison.Ordinal);
+        Assert.Contains("Path.Combine(AppContext.BaseDirectory, \"Cuts\")", resolver,
+            StringComparison.Ordinal);
+        Assert.Contains("Path.Combine(AppContext.BaseDirectory, \"Res\")", resolver,
+            StringComparison.Ordinal);
+        Assert.Contains("ResolveAutomaticBackgroundDirectory()", resolver,
+            StringComparison.Ordinal);
+        Assert.Contains("FindNearestExistingDirectory(preferredPath)", resolver,
+            StringComparison.Ordinal);
+        Assert.Contains("candidate = candidate.Parent", resolver,
+            StringComparison.Ordinal);
+        Assert.Contains("FindNearestExistingDirectory(AppContext.BaseDirectory)", resolver,
+            StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void FolderPickerTitleAndButtonRemainCompatibleWithTheLocalStateSmoke()
+    {
+        Assert.Contains("\"폴더 선택 - 디자인\"", Settings, StringComparison.Ordinal);
+        Assert.Contains("\"폴더 선택 - 설정\"", Settings, StringComparison.Ordinal);
+        Assert.Contains("\"폴더 선택 - 배경\"", Settings, StringComparison.Ordinal);
+        Assert.Contains("dialog.SetOkButtonLabel(\"폴더 선택\")", FolderPicker,
+            StringComparison.Ordinal);
+    }
+
     [Fact]
     public void SelectedFoldersAreLoadedAtStartupAndAppliedOnlyAtCompositionBoundaries()
     {
@@ -162,7 +221,7 @@ public sealed class LegacyOperatorSettingsNativeContractTests
     {
         var cancelledPicker = Slice(
             Settings,
-            "if (selected is null)",
+            "if (selectedPath is null)",
             "cancellationToken.ThrowIfCancellationRequested();");
 
         Assert.DoesNotContain(