优化更新代码，添加界面功能并整合

WPFluent/Services/INavigationWindow.cs

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+
+
+
+using WPFluent.Abstractions;
+using WPFluent.Controls;
+
+namespace WPFluent;
+
+/// <summary>
+/// Represents a contract with a <see cref="System.Windows.Window"/> that contains <see cref="INavigationView"/>.
+/// Through defined <see cref="INavigationViewPageProvider"/> service allows you to use the MVVM model in <c>WPF UI</c>
+/// navigation.
+/// </summary>
+public interface INavigationWindow
+{
+    /// <summary>
+    /// Triggers the command to close a window.
+    /// </summary>
+    void CloseWindow();
+
+    /// <summary>
+    /// Provides direct access to the control responsible for navigation.
+    /// </summary>
+    /// <returns>Instance of the <see cref="INavigationView"/> control.</returns>
+    INavigationView GetNavigation();
+
+    /// <summary>
+    /// Lets you navigate to the selected page based on it's type. Should be used with <see
+    /// cref="INavigationViewPageProvider"/>.
+    /// </summary>
+    /// <param name="pageType"><see langword="Type"/> of the page.</param>
+    /// <returns><see langword="true"/> if the operation succeeds. <see langword="false"/> otherwise.</returns>
+    bool Navigate(Type pageType);
+
+    /// <summary>
+    /// Lets you attach the service that delivers page instances to <see cref="INavigationView"/>.
+    /// </summary>
+    /// <param name="navigationViewPageProvider">Instance of the <see cref="INavigationViewPageProvider"/> with attached service provider.</param>
+    void SetPageService(INavigationViewPageProvider navigationViewPageProvider);
+
+    /// <summary>
+    /// Lets you attach the service provider that delivers page instances to <see cref="INavigationView"/>.
+    /// </summary>
+    /// <param name="serviceProvider">Instance of the <see cref="IServiceProvider"/>.</param>
+    void SetServiceProvider(IServiceProvider serviceProvider);
+
+    /// <summary>
+    /// Triggers the command to open a window.
+    /// </summary>
+    void ShowWindow();
+}