Dashboard: confirm before Close session / Kill worker

Add a shared ConfirmDialog component and route Sessions, Workers, and
SessionDetails Close/Kill buttons through it. The dialog shows the
target session id and a color-matched confirm button (yellow Close,
red Kill); Cancel dismisses without invoking the admin service.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/WorkersPage.razor

@@ -25,6 +25,18 @@ else
         </div>
     }
 
+    @if (CanManage)
+    {
+        <ConfirmDialog IsOpen="@(PendingSessionId is not null)"
+                       Title="Kill worker?"
+                       Message="@($"Forcefully kill the worker for session {PendingSessionId}? This skips graceful shutdown.")"
+                       ConfirmLabel="Kill"
+                       ConfirmButtonClass="btn-danger"
+                       IsBusy="IsBusy"
+                       OnConfirm="ConfirmKillAsync"
+                       OnCancel="CancelPending" />
+    }
+
     <section class="dashboard-section">
         @if (Snapshot.Workers.Count == 0)
         {
@@ -61,7 +73,7 @@ else
                                     <td>
                                         <button type="button" class="btn btn-sm btn-outline-danger"
                                                 disabled="@IsBusy"
-                                                @onclick="() => KillWorkerAsync(worker.SessionId)">
+                                                @onclick="() => RequestKill(worker.SessionId)">
                                             Kill
                                         </button>
                                     </td>
@@ -93,13 +105,34 @@ else
         CanManage = SessionAdminService.CanManage(authenticationState.User);
     }
 
-    private async Task KillWorkerAsync(string sessionId)
+    private string? PendingSessionId { get; set; }
+
+    private void RequestKill(string sessionId)
     {
         if (IsBusy)
         {
             return;
         }
 
+        PendingSessionId = sessionId;
+    }
+
+    private void CancelPending()
+    {
+        if (!IsBusy)
+        {
+            PendingSessionId = null;
+        }
+    }
+
+    private async Task ConfirmKillAsync()
+    {
+        if (IsBusy || PendingSessionId is null)
+        {
+            return;
+        }
+
+        string sessionId = PendingSessionId;
         IsBusy = true;
         try
         {
@@ -115,6 +148,7 @@ else
         finally
         {
             IsBusy = false;
+            PendingSessionId = null;
         }
     }
 }