Address review: handle NavigationFailed gracefully without rethrowing

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/modules/cmdpal/Microsoft.CmdPal.UI/Helpers/MarkdownImageProviders/ImageProvider.cs

@@ -22,7 +22,7 @@ internal sealed partial class ImageProvider : IImageProvider
             return RtbInlineImageFactory.Create(imageSource.ImageSource, new RtbInlineImageFactory.InlineImageOptions
             {
                 DownscaleOnly = imageSource.Hints.DownscaleOnly ?? true,
-                FitColumnWidth = imageSource.Hints.FitMode is null || imageSource.Hints.FitMode.Equals("fit", StringComparison.OrdinalIgnoreCase),
+                FitColumnWidth = imageSource.Hints.FitMode == "fit",
                 MaxWidthDip = imageSource.Hints.MaxPixelWidth,
                 MaxHeightDip = imageSource.Hints.MaxPixelHeight,
                 WidthDip = imageSource.Hints.DesiredPixelWidth,

src/modules/cmdpal/ext/SamplePagesExtension/Pages/SampleMarkdownImagesPage.cs

@@ -154,8 +154,8 @@ internal sealed partial class SampleMarkdownImagesPage : ContentPage
             For URIs that support query parameters (file, http, ms-appx, ms-appdata), you can provide hints to control scaling
             
             - `--x-cmdpal-fit`
-              - `fit`: scale to fit the available space (default)
-              - `none`: no automatic scaling, provides image as is
+              - `none`: no automatic scaling, provides image as is (default)
+              - `fit`: scale to fit the available space
             - `--x-cmdpal-upscale`
               - `true`: allow upscaling
               - `false`: downscale only (default)
@@ -169,19 +169,18 @@ internal sealed partial class SampleMarkdownImagesPage : ContentPage
             ## Examples
             
             ### No scaling
-            ℹ️ This sample uses the source pixel size, so under non-100% DPI scaling the rendered size can differ from the image's natural visual size.
             ```xml
-            ![green rectangle]({{path1}}?--x-cmdpal-fit=none)
+            ![green rectangle]({{path1}})
             ```
             
-            ![green rectangle]({{path1}}?--x-cmdpal-fit=none)
+            ![green rectangle]({{path1}})
             
             ### Scale to fit (scaling down only by default)
             ```xml
-            ![green rectangle]({{path1}})
+            ![green rectangle]({{path1}}?--x-cmdpal-fit=fit)
             ```
 
-            ![green rectangle]({{path1}})
+            ![green rectangle]({{path1}}?--x-cmdpal-fit=fit)
             
             ### Scale to fit (in both direction)
             ```xml

src/settings-ui/Settings.UI/ViewModels/ShellViewModel.cs

@@ -9,6 +9,7 @@ using System.Linq;
 using System.Threading.Tasks;
 using System.Windows.Input;
 
+using ManagedCommon;
 using Microsoft.PowerToys.Settings.UI.Helpers;
 using Microsoft.PowerToys.Settings.UI.Library;
 using Microsoft.PowerToys.Settings.UI.Library.Helpers;
@@ -135,7 +136,18 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
 
         private void Frame_NavigationFailed(object sender, NavigationFailedEventArgs e)
         {
-            throw e.Exception;
+            var sourcePage = e.SourcePageType?.FullName ?? "<unknown>";
+
+            if (e.Exception is null)
+            {
+                Logger.LogWarning($"Navigation to '{sourcePage}' failed without an exception.");
+            }
+            else
+            {
+                Logger.LogError($"Navigation to '{sourcePage}' failed.", e.Exception);
+            }
+
+            e.Handled = true;
         }
 
         private void Frame_Navigated(object sender, NavigationEventArgs e)