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/IHasProviderIds.cs

@@ -2,19 +2,17 @@
 // Copyright (c) PlaceholderCompany. All rights reserved.
 // </copyright>
 
-using System.Collections.Generic;
+namespace MediaBrowser.Model.Entities;
+   using global::System.Collections.Generic;
 
-namespace MediaBrowser.Model.Entities
-{
-    /// <summary>
-    /// Since BaseItem and DTOBaseItem both have ProviderIds, this interface helps avoid code repetition by using extension methods.
-    /// </summary>
-    public interface IHasProviderIds
-    {
-        /// <summary>
-        /// Gets or sets the provider ids.
-        /// </summary>
-        /// <value>The provider ids.</value>
-        Dictionary<string, string> ProviderIds { get; set; }
-    }
-}
+   /// <summary>
+   /// Since BaseItem and DTOBaseItem both have ProviderIds, this interface helps avoid code repetition by using extension methods.
+   /// </summary>
+   public interface IHasProviderIds
+   {
+       /// <summary>
+       /// Gets or sets the provider ids.
+       /// </summary>
+       /// <value>The provider ids.</value>
+       Dictionary<string, string> ProviderIds { get; set; }
+   }