fix(adminui): wire Test Connect probes + live panels on admin-only nodes

Both bugs surfaced only on split-role deployments (the MAIN cluster's
admin-only nodes), where the AdminUI runs without the driver role.

- Test Connect returned "No probe registered" for every driver: the
  IDriverProbe set was registered only under the driver role, but the
  admin-operations singleton that consumes it is pinned to admin. Extract
  AddOtOpcUaDriverProbes() (idempotent via TryAddEnumerable) and call it
  in the hasAdmin path too.

- Live driver-status/alerts/script-log panels showed "SignalR error:
  Connection refused": these Blazor Server components opened a HubConnection
  to their own hub via the browser's public URL, which server-side code
  can't reach behind Traefik (host :9200 -> container :9000). Read the
  in-process source directly instead -- DriverStatus via
  IDriverStatusSnapshotStore.SnapshotChanged, Alerts/ScriptLog via a new
  IInProcessBroadcaster<T>. Fleet status was unaffected (reads DB/ActorSystem).

Adds unit tests for probe registration, the snapshot-store event, and the
broadcaster.

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Shared/Drivers/DriverStatusPanel.razor

@@ -4,14 +4,14 @@
    DriverOperator-gated Reconnect/Restart buttons appear for authorised users. *@
 @implements IAsyncDisposable
 @using Microsoft.AspNetCore.Authorization
-@using Microsoft.AspNetCore.SignalR.Client
+@using ZB.MOM.WW.OtOpcUa.AdminUI.Hubs
 @using ZB.MOM.WW.OtOpcUa.Commons.Interfaces
 @using ZB.MOM.WW.OtOpcUa.Commons.Messages.Admin
 @using ZB.MOM.WW.OtOpcUa.Commons.Messages.Drivers
-@inject NavigationManager Nav
 @inject AuthenticationStateProvider AuthState
 @inject IAuthorizationService AuthorizationService
 @inject IAdminOperationsClient AdminOps
+@inject IDriverStatusSnapshotStore StatusStore
 
 <section class="panel rise mt-3" style="animation-delay:.04s; @(_stale ? "opacity:0.5;" : "")">
     <div class="panel-head d-flex align-items-center gap-2">
@@ -139,7 +139,6 @@
     [Parameter] public string ClusterId { get; set; } = "";
     [Parameter] public bool Enabled { get; set; } = true;
 
-    private HubConnection? _hub;
     private DriverHealthChanged? _snapshot;
     private DateTime _lastUpdateUtc = DateTime.MinValue;
     private bool _stale;
@@ -180,30 +179,44 @@
             InvokeAsync(StateHasChanged);
         }, null, TimeSpan.FromSeconds(5), TimeSpan.FromSeconds(5));
 
-        _hub = new HubConnectionBuilder()
-            .WithUrl(Nav.ToAbsoluteUri("/hubs/driverstatus"))
-            .WithAutomaticReconnect()
-            .Build();
-
-        _hub.On<DriverHealthChanged>("status", snap =>
-        {
-            _snapshot = snap;
-            _lastUpdateUtc = DateTime.UtcNow;
-            _stale = false;
-            InvokeAsync(StateHasChanged);
-        });
-
+        // Read live status straight from the in-process snapshot store rather than opening a
+        // self-targeted SignalR connection. This component runs server-side (Blazor
+        // InteractiveServer), so a HubConnection to the browser's public URL (e.g.
+        // http://localhost:9200 behind Traefik) would dial that port from *inside* the container —
+        // where only Kestrel's :9000 listens — and fail with "Connection refused". The store is fed
+        // on every admin node by DriverStatusSignalRBridge (a per-node DistributedPubSub
+        // subscriber), so the local singleton is always current regardless of which replica serves
+        // this circuit.
         try
         {
-            await _hub.StartAsync();
-            _connecting = false;
-            await _hub.InvokeAsync("JoinDriver", DriverInstanceId);
+            StatusStore.SnapshotChanged += OnSnapshotChanged;
+            if (StatusStore.TryGet(DriverInstanceId, out var snap))
+            {
+                _snapshot = snap;
+                _lastUpdateUtc = DateTime.UtcNow;
+            }
         }
         catch (Exception ex)
         {
-            _connecting = false;
             _error = ex.Message;
         }
+        finally
+        {
+            _connecting = false;
+        }
+    }
+
+    // Invoked by the snapshot store (on the bridge actor's thread) for every driver instance;
+    // ignore snapshots for other instances and marshal onto the render sync context.
+    private void OnSnapshotChanged(DriverHealthChanged snap)
+    {
+        if (!string.Equals(snap.DriverInstanceId, DriverInstanceId, StringComparison.Ordinal))
+            return;
+
+        _snapshot = snap;
+        _lastUpdateUtc = DateTime.UtcNow;
+        _stale = false;
+        InvokeAsync(StateHasChanged);
     }
 
     private async Task ReconnectAsync()
@@ -285,12 +298,13 @@
 
     public async ValueTask DisposeAsync()
     {
-        // Drain BOTH timers first so an in-flight callback can't invoke StateHasChanged on
-        // a component whose hub has already been released. System.Threading.Timer's async
-        // dispose awaits any in-flight callback (.NET 6+).
+        // Unsubscribe first so the singleton store can't invoke a handler on a disposed component.
+        StatusStore.SnapshotChanged -= OnSnapshotChanged;
+        // Drain BOTH timers so an in-flight callback can't invoke StateHasChanged on a component
+        // that's already gone. System.Threading.Timer's async dispose awaits any in-flight
+        // callback (.NET 6+).
         if (_timer is not null) await _timer.DisposeAsync();
         if (_opResultClearTimer is not null) await _opResultClearTimer.DisposeAsync();
-        if (_hub is not null) await _hub.DisposeAsync();
     }
 
     // Map DriverState string → chip CSS class using the 4 defined theme variants.