Refactor: standardize namespace and using directive style

Refactored all C# test files to use explicit namespace declarations and moved all using directives inside the namespace block for consistency. Updated assembly info and cache files to reflect the new build. Adjusted MvcTestingAppManifest.json to use fully qualified assembly names. No functional changes; all updates are related to code style, organization, and project metadata.

MediaBrowser.Model/Session/UserDataChangeInfo.cs

@@ -2,26 +2,24 @@
 // Copyright (c) PlaceholderCompany. All rights reserved.
 // </copyright>
 
-using System;
-using MediaBrowser.Model.Dto;
+namespace MediaBrowser.Model.Session;
+   using global::System;
+   using MediaBrowser.Model.Dto;
 
-namespace MediaBrowser.Model.Session
-{
-    /// <summary>
-    /// Class UserDataChangeInfo.
-    /// </summary>
-    public class UserDataChangeInfo
-    {
-        /// <summary>
-        /// Gets or sets the user id.
-        /// </summary>
-        /// <value>The user id.</value>
-        public Guid UserId { get; set; }
+   /// <summary>
+   /// Class UserDataChangeInfo.
+   /// </summary>
+   public class UserDataChangeInfo
+   {
+       /// <summary>
+       /// Gets or sets the user id.
+       /// </summary>
+       /// <value>The user id.</value>
+       public Guid UserId { get; set; }
 
-        /// <summary>
-        /// Gets or sets the user data list.
-        /// </summary>
-        /// <value>The user data list.</value>
-        public required UserItemDataDto[] UserDataList { get; set; }
-    }
-}
+       /// <summary>
+       /// Gets or sets the user data list.
+       /// </summary>
+       /// <value>The user data list.</value>
+       public required UserItemDataDto[] UserDataList { get; set; }
+   }