feat: (core/ThemeKeys) add keys for Expander & SettingsExpander resources

Author: NotYoojun

source/iNKORE.UI.WPF.Modern/ThemeKeys.ThemeResources.cs

@@ -3,6 +3,7 @@
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using System.Windows;
 
 namespace iNKORE.UI.WPF.Modern
 {
@@ -362,5 +363,12 @@ public static partial class ThemeKeys
         public static readonly string ToolTipMaxWidthKey = "ToolTipMaxWidth";
         public static readonly string TreeViewItemPillMinScaleKey = "TreeViewItemPillMinScale";
         public static readonly string TreeViewItemScaleAnimationDurationKey = "TreeViewItemScaleAnimationDuration";
+
+        public static readonly string ExpandAnimationDurationKey = "ExpandAnimationDuration";
+        public static readonly string CollapseAnimationDurationKey = "CollapseAnimationDuration";
+
+        public static readonly string SettingsExpanderChevronToolTipKey = "SettingsExpanderChevronToolTip";
+        public static readonly string SettingsExpanderHeaderPaddingKey = "SettingsExpanderHeaderPadding";
+        public static readonly string SettingsExpanderItemPaddingKey = "SettingsExpanderItemPadding";
     }
 }