Fix: subscribe to ItemsChanged before fetching items to avoid missing early events

Agent-Logs-Url: https://github.com/microsoft/PowerToys/sessions/3f380bd3-a56a-4708-80ef-3e7d534c4f6f

Co-authored-by: MuyuanMS <116717757+MuyuanMS@users.noreply.github.com>

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ContentPageViewModel.cs

@@ -129,8 +129,8 @@ public partial class ContentPageViewModel : PageViewModel, ICommandBarContext
 
         UpdateDetails();
 
-        FetchContent();
         model.ItemsChanged += Model_ItemsChanged;
+        FetchContent();
 
         DoOnUiThread(
         () =>

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ContentTreeViewModel.cs

@@ -44,9 +44,9 @@ public partial class ContentTreeViewModel(ITreeContent _tree, WeakReference<IPag
             UpdateProperty(nameof(Root));
         }
 
-        FetchContent();
         model.PropChanged += Model_PropChanged;
         model.ItemsChanged += Model_ItemsChanged;
+        FetchContent();
     }
 
     // Theoretically, we should unify this with the one in CommandPalettePageViewModelFactory

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Dock/DockBandViewModel.cs

@@ -209,8 +209,8 @@ public sealed partial class DockBandViewModel : ExtensionObjectViewModel
         var list = command.Model.Unsafe as IListPage;
         if (list is not null)
         {
-            InitializeFromList(list);
             list.ItemsChanged += HandleItemsChanged;
+            InitializeFromList(list);
         }
         else
         {

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ListViewModel.cs

@@ -957,8 +957,8 @@ public partial class ListViewModel : PageViewModel, IDisposable
         Filters?.InitializeProperties();
         UpdateProperty(nameof(Filters));
 
-        FetchItems(true);
         model.ItemsChanged += Model_ItemsChanged;
+        FetchItems(true);
     }
 
     private static IGridPropertiesViewModel? LoadGridPropertiesViewModel(IGridProperties? gridProperties)

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