优化更新代码，添加界面功能并整合

WPFluent/Controls/Window/WindowCornerPreference.cs

@@ -0,0 +1,31 @@
+
+
+
+// ReSharper disable once CheckNamespace
+namespace WPFluent.Controls;
+
+/// <summary>
+/// Ways you can round windows.
+/// </summary>
+public enum WindowCornerPreference
+{
+    /// <summary>
+    /// Determined by system or application preference.
+    /// </summary>
+    Default,
+
+    /// <summary>
+    /// Do not round the corners.
+    /// </summary>
+    DoNotRound,
+
+    /// <summary>
+    /// Round the corners.
+    /// </summary>
+    Round,
+
+    /// <summary>
+    /// Round the corners slightly.
+    /// </summary>
+    RoundSmall,
+}