Add project files.

rusnova/Pages/Error.cshtml.cs

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+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.RazorPages;
+using System.Diagnostics;
+
+namespace rusnova.Pages
+{
+	[ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
+	[IgnoreAntiforgeryToken]
+	public class ErrorModel : PageModel
+	{
+		public string? RequestId { get; set; }
+
+		public bool ShowRequestId => !string.IsNullOrEmpty(RequestId);
+
+		private readonly ILogger<ErrorModel> _logger;
+
+		public ErrorModel(ILogger<ErrorModel> logger)
+		{
+			_logger = logger;
+		}
+
+		public void OnGet()
+		{
+			RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier;
+		}
+	}
+}