fix: open folder pickers at current paths

src/MBN_STOCK_WEBVIEW.LegacyParityApp/MainWindow.Settings.cs

@@ -2,8 +2,6 @@ using MBN_STOCK_WEBVIEW.Infrastructure;
 using MBN_STOCK_WEBVIEW.LegacyApplication;
 using MBN_STOCK_WEBVIEW.LegacyBridge;
 using MMoneyCoderSharp.Data;
-using Windows.Storage.Pickers;
-using WinRT.Interop;
 
 namespace MBN_STOCK_WEBVIEW.LegacyParityApp;
 
@@ -85,18 +83,11 @@ public sealed partial class MainWindow
         cancellationToken.ThrowIfCancellationRequested();
         try
         {
-            var picker = new FolderPicker
-            {
-                SuggestedStartLocation = PickerLocationId.ComputerFolder,
-                ViewMode = PickerViewMode.List
-            };
-            picker.FileTypeFilter.Add("*");
-            var owner = _windowHandle != 0
-                ? _windowHandle
-                : WindowNative.GetWindowHandle(this);
-            InitializeWithWindow.Initialize(picker, owner);
-            var selected = await picker.PickSingleFolderAsync();
-            if (selected is null)
+            var initialDirectory = ResolveOperatorFolderPickerStartDirectory(kind);
+            var selectedPath = await PickOperatorFolderAsync(
+                initialDirectory,
+                ResolveOperatorFolderPickerTitle(kind));
+            if (selectedPath is null)
             {
                 return;
             }
@@ -105,7 +96,7 @@ public sealed partial class MainWindow
             var validationKind = ToSettingsFolderKind(kind);
             if (!LegacyOperatorFolderValidator.TryValidate(
                     validationKind,
-                    selected.Path,
+                    selectedPath,
                     out var validated,
                     out var warningMessage) ||
                 validated is null)
@@ -156,6 +147,81 @@ public sealed partial class MainWindow
         }
     }
 
+    private string? ResolveOperatorFolderPickerStartDirectory(
+        LegacyOperatorFolderKind kind)
+    {
+        var preferredPath = kind switch
+        {
+            LegacyOperatorFolderKind.Design =>
+                _operatorSettings.SceneDirectory ??
+                Path.Combine(AppContext.BaseDirectory, "Cuts"),
+            LegacyOperatorFolderKind.Resource =>
+                _operatorSettings.ResourceDirectory ??
+                Path.Combine(AppContext.BaseDirectory, "Res"),
+            LegacyOperatorFolderKind.Background =>
+                _operatorSettings.BackgroundDirectory ??
+                ResolveAutomaticBackgroundDirectory(),
+            _ => throw new ArgumentOutOfRangeException(nameof(kind))
+        };
+
+        return FindNearestExistingDirectory(preferredPath) ??
+            FindNearestExistingDirectory(AppContext.BaseDirectory);
+    }
+
+    private string ResolveAutomaticBackgroundDirectory()
+    {
+        var sceneDirectory = _operatorSettings.SceneDirectory ??
+            Path.Combine(AppContext.BaseDirectory, "Cuts");
+        var canonicalSceneDirectory = Path.TrimEndingDirectorySeparator(
+            Path.GetFullPath(sceneDirectory));
+        var sceneParent = Path.GetDirectoryName(canonicalSceneDirectory);
+        return Path.Combine(
+            sceneParent ?? AppContext.BaseDirectory,
+            "배경");
+    }
+
+    private static string? FindNearestExistingDirectory(string? path)
+    {
+        if (string.IsNullOrWhiteSpace(path) ||
+            !Path.IsPathFullyQualified(path))
+        {
+            return null;
+        }
+
+        try
+        {
+            for (var candidate = new DirectoryInfo(Path.GetFullPath(path));
+                 candidate is not null;
+                 candidate = candidate.Parent)
+            {
+                if (candidate.Exists)
+                {
+                    return candidate.FullName;
+                }
+            }
+        }
+        catch (Exception exception) when (
+            exception is ArgumentException or
+            IOException or
+            NotSupportedException or
+            System.Security.SecurityException or
+            UnauthorizedAccessException)
+        {
+            return null;
+        }
+
+        return null;
+    }
+
+    private static string ResolveOperatorFolderPickerTitle(
+        LegacyOperatorFolderKind kind) => kind switch
+        {
+            LegacyOperatorFolderKind.Design => "폴더 선택 - 디자인",
+            LegacyOperatorFolderKind.Resource => "폴더 선택 - 설정",
+            LegacyOperatorFolderKind.Background => "폴더 선택 - 배경",
+            _ => throw new ArgumentOutOfRangeException(nameof(kind))
+        };
+
     private void ResetOperatorFolder(LegacyOperatorFolderKind kind)
     {
         var next = kind switch