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/Entities/ProviderIdsExtensions.cs

@@ -2,13 +2,13 @@
 // Copyright (c) PlaceholderCompany. All rights reserved.
 // </copyright>
 
-using System;
-using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
-using System.Linq;
-
 namespace MediaBrowser.Model.Entities;
 
+using global::System;
+using global::System.Collections.Generic;
+using global::System.Diagnostics.CodeAnalysis;
+using global::System.Linq;
+
 /// <summary>
 /// Class ProviderIdsExtensions.
 /// </summary>
@@ -60,6 +60,7 @@ public static class ProviderIdsExtensions
         }
 
         var foundProviderId = instance.ProviderIds.TryGetValue(name, out id);
+
         // This occurs when searching with Identify (and possibly in other places)
         if (string.IsNullOrEmpty(id))
         {