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.Domain/Aggregates/Session.cs

@@ -1,41 +1,32 @@
 using Shogi.Domain.ValueObjects;
 
-namespace Shogi.Domain;
+namespace Shogi.Domain.Aggregates;
 
-public class Session
+public class Session(Guid id, string player1Name)
 {
-    public Session(
-      string name,
-      string player1Name)
-    {
-        Name = name;
-        Player1 = player1Name;
-        Board = new(BoardState.StandardStarting);
-    }
+	public Guid Id { get; } = id;
 
-    public string Name { get; }
+	public ShogiBoard Board { get; } = new(BoardState.StandardStarting);
 
-    public ShogiBoard Board { get; }
+	/// <summary>
+	/// The email of the player which created the session.
+	/// </summary>
+	public string Player1 { get; } = player1Name;
 
-    /// <summary>
-    /// The User.Id of the player which created the session.
-    /// </summary>
-    public string Player1 { get; }
+	/// <summary>
+	/// The email of the second player.
+	/// </summary>
+	public string? Player2 { get; private set; }
 
-    /// <summary>
-    /// The User.Id of the second player.
-    /// </summary>
-    public string? Player2 { get; private set; }
+	public void AddPlayer2(string player2Name)
+	{
+		if (this.Player2 != null) throw new InvalidOperationException("Player 2 already exists while trying to add a second player.");
+		if (this.Player1.Equals(player2Name, StringComparison.OrdinalIgnoreCase)) throw new InvalidOperationException("Player 2 must be different from Player 1");
+		this.Player2 = player2Name;
+	}
 
-    public void AddPlayer2(string player2Name)
-    {
-        if (Player2 != null) throw new InvalidOperationException("Player 2 already exists while trying to add a second player.");
-        if (Player1.Equals(player2Name, StringComparison.OrdinalIgnoreCase)) throw new InvalidOperationException("Player 2 must be different from Player 1");
-        Player2 = player2Name;
-    }
-
-    public bool IsSeated(string playerName)
-    {
-        return Player1 == playerName || Player2 == playerName;
-    }
+	public bool IsSeated(string playerName)
+	{
+		return this.Player1 == playerName || this.Player2 == playerName;
+	}
 }