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.

Emby.Server.Implementations/AppBase/BaseApplicationPaths.cs

@@ -2,15 +2,15 @@
 // Copyright (c) PlaceholderCompany. All rights reserved.
 // </copyright>
 
-using System;
-using System.Collections.Generic;
-using System.IO;
-using System.Linq;
-using Jellyfin.Extensions;
-using MediaBrowser.Common.Configuration;
-
 namespace Emby.Server.Implementations.AppBase
 {
+    using System;
+    using System.Collections.Generic;
+    using System.IO;
+    using System.Linq;
+    using Jellyfin.Extensions;
+    using MediaBrowser.Common.Configuration;
+
     /// <summary>
     /// Provides a base class to hold common application paths used by both the UI and Server.
     /// This can be subclassed to add application-specific paths.

Emby.Server.Implementations/AppBase/BaseConfigurationManager.cs

@@ -2,22 +2,22 @@
 // Copyright (c) PlaceholderCompany. All rights reserved.
 // </copyright>
 
-using System;
-using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Globalization;
-using System.IO;
-using System.Linq;
-using System.Threading;
-using MediaBrowser.Common.Configuration;
-using MediaBrowser.Common.Events;
-using MediaBrowser.Common.Extensions;
-using MediaBrowser.Model.Configuration;
-using MediaBrowser.Model.Serialization;
-using Microsoft.Extensions.Logging;
-
 namespace Emby.Server.Implementations.AppBase
 {
+    using System;
+    using System.Collections.Concurrent;
+    using System.Collections.Generic;
+    using System.Globalization;
+    using System.IO;
+    using System.Linq;
+    using System.Threading;
+    using MediaBrowser.Common.Configuration;
+    using MediaBrowser.Common.Events;
+    using MediaBrowser.Common.Extensions;
+    using MediaBrowser.Model.Configuration;
+    using MediaBrowser.Model.Serialization;
+    using Microsoft.Extensions.Logging;
+
     /// <summary>
     /// Class BaseConfigurationManager.
     /// </summary>

Emby.Server.Implementations/AppBase/ConfigurationHelper.cs

@@ -2,12 +2,12 @@
 // Copyright (c) PlaceholderCompany. All rights reserved.
 // </copyright>
 
-using System;
-using System.IO;
-using MediaBrowser.Model.Serialization;
-
 namespace Emby.Server.Implementations.AppBase
 {
+    using System;
+    using System.IO;
+    using MediaBrowser.Model.Serialization;
+
     /// <summary>
     /// Class ConfigurationHelper.
     /// </summary>