Fix low-contrast price and date text in saved listings cards

Price text changed from Accent brush (~3.4:1) to ThemeForeground (white)
for WCAG AA compliance. Date text changed from Gray5 (~3.2:1) to Gray3.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

EbayListingTool/Views/SavedListingsView.xaml.cs

@@ -188,7 +188,7 @@ public partial class SavedListingsView : UserControl
             Text = listing.PriceDisplay,
             FontSize = 13,
             FontWeight = FontWeights.Bold,
-            Foreground = (Brush)FindResource("MahApps.Brushes.Accent"),
+            Foreground = (Brush)FindResource("MahApps.Brushes.ThemeForeground"),
             Margin = new Thickness(0, 0, 8, 0)
         });
         textStack.Children.Add(priceRow);
@@ -197,7 +197,7 @@ public partial class SavedListingsView : UserControl
         {
             Text = listing.SavedAtDisplay,
             FontSize = 10,
-            Foreground = (Brush)FindResource("MahApps.Brushes.Gray5"),
+            Foreground = (Brush)FindResource("MahApps.Brushes.Gray3"),
             Margin = new Thickness(0, 3, 0, 0)
         });