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/Configuration/MetadataPlugin.cs

@@ -5,20 +5,18 @@
 #nullable disable
 #pragma warning disable CS1591
 
-namespace MediaBrowser.Model.Configuration
-{
-    public class MetadataPlugin
-    {
-        /// <summary>
-        /// Gets or sets the name.
-        /// </summary>
-        /// <value>The name.</value>
-        public string Name { get; set; }
+namespace MediaBrowser.Model.Configuration;
+   public class MetadataPlugin
+   {
+       /// <summary>
+       /// Gets or sets the name.
+       /// </summary>
+       /// <value>The name.</value>
+       public string Name { get; set; }
 
-        /// <summary>
-        /// Gets or sets the type.
-        /// </summary>
-        /// <value>The type.</value>
-        public MetadataPluginType Type { get; set; }
-    }
-}
+       /// <summary>
+       /// Gets or sets the type.
+       /// </summary>
+       /// <value>The type.</value>
+       public MetadataPluginType Type { get; set; }
+   }