Dashboard: admin-only Close session / Kill worker

Add IDashboardSessionAdminService (Admin-role gate, friendly errors,
audit logging) wrapping a new ISessionManager.KillWorkerAsync that
skips graceful shutdown and cleans up registry/metrics. Sessions,
Workers, and SessionDetails pages render Close / Kill buttons only
when CanManage; the service re-checks the role on every call so
forged clicks return Unauthenticated.

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

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

@@ -1,5 +1,7 @@
 @page "/workers"
 @inherits DashboardPageBase
+@inject AuthenticationStateProvider AuthenticationStateProvider
+@inject IDashboardSessionAdminService SessionAdminService
 
 <PageTitle>Dashboard Workers</PageTitle>
 
@@ -16,6 +18,13 @@ else
         </div>
     </div>
 
+    @if (CanManage && !string.IsNullOrWhiteSpace(ResultMessage))
+    {
+        <div class="alert @(LastOperationSucceeded ? "alert-success" : "alert-danger")" role="alert">
+            @ResultMessage
+        </div>
+    }
+
     <section class="dashboard-section">
         @if (Snapshot.Workers.Count == 0)
         {
@@ -32,6 +41,10 @@ else
                             <th scope="col">Session</th>
                             <th scope="col">Heartbeat</th>
                             <th scope="col">Fault</th>
+                            @if (CanManage)
+                            {
+                                <th scope="col">Actions</th>
+                            }
                         </tr>
                     </thead>
                     <tbody>
@@ -43,6 +56,16 @@ else
                                 <td><NavLink href="@($"sessions/{Uri.EscapeDataString(worker.SessionId)}")"><code>@worker.SessionId</code></NavLink></td>
                                 <td>@DashboardDisplay.DateTime(worker.LastHeartbeatAt)</td>
                                 <td>@DashboardDisplay.Text(worker.LastFault)</td>
+                                @if (CanManage)
+                                {
+                                    <td>
+                                        <button type="button" class="btn btn-sm btn-outline-danger"
+                                                disabled="@IsBusy"
+                                                @onclick="() => KillWorkerAsync(worker.SessionId)">
+                                            Kill
+                                        </button>
+                                    </td>
+                                }
                             </tr>
                         }
                     </tbody>
@@ -51,3 +74,47 @@ else
         }
     </section>
 }
+
+@code {
+    private bool CanManage { get; set; }
+
+    private bool IsBusy { get; set; }
+
+    private string? ResultMessage { get; set; }
+
+    private bool LastOperationSucceeded { get; set; }
+
+    protected override async Task OnInitializedAsync()
+    {
+        await base.OnInitializedAsync().ConfigureAwait(false);
+
+        AuthenticationState authenticationState = await AuthenticationStateProvider.GetAuthenticationStateAsync()
+            .ConfigureAwait(false);
+        CanManage = SessionAdminService.CanManage(authenticationState.User);
+    }
+
+    private async Task KillWorkerAsync(string sessionId)
+    {
+        if (IsBusy)
+        {
+            return;
+        }
+
+        IsBusy = true;
+        try
+        {
+            AuthenticationState authenticationState = await AuthenticationStateProvider.GetAuthenticationStateAsync()
+                .ConfigureAwait(false);
+            CanManage = SessionAdminService.CanManage(authenticationState.User);
+            DashboardSessionAdminResult result = await SessionAdminService
+                .KillWorkerAsync(authenticationState.User, sessionId, CancellationToken.None)
+                .ConfigureAwait(false);
+            ResultMessage = result.Message;
+            LastOperationSucceeded = result.Succeeded;
+        }
+        finally
+        {
+            IsBusy = false;
+        }
+    }
+}