Replace custom socket implementation with SignalR.

Replace MSAL and custom cookie auth with Microsoft.Identity.EntityFramework
Also some UI redesign to accommodate different login experience.

Shogi.Api/ApiKeys.cs

@@ -0,0 +1,6 @@
+namespace Shogi.Api;
+
+public class ApiKeys
+{
+	public string BrevoEmailService { get; set; } = string.Empty;
+}