Fix a layout.

src/Aiursoft.ChessServer/Controllers/HomeController.cs

@@ -1,6 +1,8 @@
+using Aiursoft.AiurObserver;
 using Aiursoft.ChessServer.Data;
 using Aiursoft.ChessServer.Models;
 using Aiursoft.CSTools.Services;
+using Aiursoft.WebTools.Services;
 using Microsoft.AspNetCore.Mvc;
 
 namespace Aiursoft.ChessServer.Controllers;
@@ -144,4 +146,30 @@ public class HomeController : Controller
         }
         return RedirectToAction(nameof(Index));
     }
+
+    public async Task ListenChallenge(int id)
+    {
+        var pusher = await HttpContext.AcceptWebSocketClient();
+        var challenge = _database.GetChallenge(id);
+        if (challenge == null)
+        {
+            return;
+        }
+        var outSub = challenge
+            .ChallengeChangedChannel
+            .Subscribe(t => pusher.Send(t, HttpContext.RequestAborted));
+        try
+        {
+            await pusher.Listen(HttpContext.RequestAborted);
+        }
+        catch (TaskCanceledException)
+        {
+            // Ignore. This happens when the client closes the connection.
+        }
+        finally
+        {
+            await pusher.Close(HttpContext.RequestAborted);
+            outSub.Unsubscribe();
+        }
+    }
 }

src/Aiursoft.ChessServer/Views/Games/GetHtml.cshtml

@@ -1,5 +1,10 @@
 @model int
 
-<div class="row">
-<vc:chess-board game-id="@Model"></vc:chess-board>
-</div>
+<div class="container mt-5">
+    <main role="main" class="pb-3">
+        <div class="row">
+        <vc:chess-board game-id="@Model"></vc:chess-board>
+        </div>
+    </main>
+</div>
+