[Peek] Fix Space key triggering during file rename (#44845) (#44995)

Don't show error window when CurrentItem is null - just return silently.
This restores the original behavior where CaretVisible() detection in
GetSelectedItems() would suppress Peek by returning null, and no window
would be shown.

PR #44703 added an error window for virtual folders (Home/Recent), but
this also triggered when user was typing (rename, search, address bar),
stealing focus and cancelling the operation.

Fixes #44845

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## Summary of the Pull Request

src/modules/peek/Peek.UI/PeekXAML/MainWindow.xaml.cs

@@ -197,16 +197,10 @@ namespace Peek.UI
 
             ViewModel.Initialize(selectedItem);
 
-            // If no files were found (e.g., in virtual folders like Home/Recent), show an error
+            // If no files were found (e.g., user is typing in rename/search box, or in virtual folders),
+            // don't show anything - just return silently to avoid stealing focus
             if (ViewModel.CurrentItem == null)
             {
-                Logger.LogInfo("Peek: No files found to preview, showing error.");
-                var errorMessage = ResourceLoaderInstance.ResourceLoader.GetString("NoFilesSelected");
-                ViewModel.ShowError(errorMessage);
-
-                // Still show the window so user can see the warning
-                this.Show();
-                WindowHelpers.BringToForeground(this.GetWindowHandle());
                 return;
             }