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.UI/Pages/Play/PromotePrompt.cs

@@ -0,0 +1,58 @@
+using Shogi.Contracts.Api;
+using Shogi.UI.Shared;
+
+namespace Shogi.UI.Pages.Play;
+
+public class PromotePrompt
+{
+  private readonly ShogiApi shogiApi;
+  private string? sessionName;
+  private MovePieceCommand? command;
+
+  public PromotePrompt(ShogiApi shogiApi)
+  {
+    this.shogiApi = shogiApi;
+		this.IsVisible = false;
+		this.OnClickCancel = this.Hide;
+  }
+
+  public bool IsVisible { get; private set; }
+  public Action OnClickCancel;
+  public Func<Task>? OnClickNo;
+  public Func<Task>? OnClickYes;
+
+  public void Show(string sessionName, MovePieceCommand command)
+  {
+    this.sessionName = sessionName;
+    this.command = command;
+		this.IsVisible = true;
+		this.OnClickNo = this.Move;
+		this.OnClickYes = this.MoveAndPromote;
+  }
+
+  public void Hide()
+  {
+		this.IsVisible = false;
+		this.OnClickNo = null;
+		this.OnClickYes = null;
+  }
+
+  private Task Move()
+  {
+    if (this.command != null && this.sessionName != null)
+    {
+			this.command.IsPromotion = false;
+      return this.shogiApi.Move(this.sessionName, this.command);
+    }
+    return Task.CompletedTask;
+  }
+  private Task MoveAndPromote()
+  {
+    if (this.command != null && this.sessionName != null)
+    {
+			this.command.IsPromotion = true;
+      return this.shogiApi.Move(this.sessionName, this.command);
+    }
+    return Task.CompletedTask;
+  }
+}