feat(adminui): F15.3 closes F15 — live alerts/script-log, CSV import, Monaco editor

Final F15 batch wires up the SignalR-backed live pages, ports the bulk
equipment importer, and progressively enhances the Script source editor
with Monaco.

Message contracts:
- Commons.Messages.Alerts.AlarmTransitionEvent — fires on every alarm
  state transition; published on the `alerts` DPS topic by future
  ScriptedAlarmActor (F9) emits.
- Commons.Messages.Logging.ScriptLogEntry — one log line emitted by a
  hosted script; published on the `script-logs` DPS topic by future
  VirtualTagActor (F8) + ScriptedAlarmActor (F9) emits.
  (Folder named "Logging" to dodge .gitignore's "logs/" rule.)

SignalR plumbing:
- AlertHub gains MethodName + bridge actor (AlertSignalRBridge)
- ScriptLogHub introduced; ScriptLogSignalRBridge follows the same
  DPS-subscribe → IHubContext fan-out pattern as FleetStatusSignalRBridge
- WithOtOpcUaSignalRBridges now spawns all three bridges
- MapOtOpcUaHubs maps /hubs/script-log alongside the existing hubs

Pages:
- /alerts                      live alarm tail, 200-row capacity
- /script-log                  live script-log tail with level + script
                               filter, 500-row capacity
- /clusters/{id}/equipment/import — CSV bulk Equipment add with preview
                                    (Name/MachineCode/UnsLineId/Driver +
                                    optional ZTag/SAPID/Manufacturer/Model;
                                    skips rows whose MachineCode already
                                    exists in the fleet)
- ScriptEdit progressively enhanced with Monaco editor via JSInterop —
  the textarea remains Blazor's source of truth and Monaco syncs into it
  on every keystroke so @bind keeps working; falls back gracefully if
  the CDN is unreachable.

MainLayout nav gains a "Live" section (Deployments, Alerts, Alarms
historian) and a "Scripts" link under Scripting. ClusterEquipment
surfaces the new Import CSV button.

Tally: F15 ships ~42 razor pages + 3 SignalR hubs + 3 bridge actors.
Microsoft.AspNetCore.SignalR.Client added (was already in central PM).

All 104 v2 tests remain green.

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/ScriptEdit.razor

@@ -13,6 +13,7 @@
 @using ZB.MOM.WW.OtOpcUa.Configuration.Entities
 @inject IDbContextFactory<OtOpcUaConfigDbContext> DbFactory
 @inject NavigationManager Nav
+@inject IJSRuntime JS
 
 <div class="d-flex justify-content-between align-items-center mb-3">
     <h4 class="mb-0">@(IsNew ? "New script" : "Edit script")</h4>
@@ -56,10 +57,15 @@ else
         <section class="panel rise mt-3">
             <div class="panel-head">Source</div>
             <div style="padding:1rem">
-                <InputTextArea @bind-Value="_form.SourceCode" class="form-control form-control-sm mono"
-                               rows="20"
-                               placeholder="// C# expression body — Monaco editor lands in a follow-up." />
-                <div class="form-text">SHA-256 hash is computed automatically on save.</div>
+                @* The textarea stays in the DOM and remains Blazor's source of truth. Monaco
+                   mounts a <div> beside it (textarea hides), and the loader's onDidChangeModelContent
+                   handler mirrors edits back into the textarea + fires the input event so @bind
+                   picks them up. Falls back to the textarea gracefully if Monaco's CDN is
+                   unreachable (air-gapped deployments — see monaco-loader.js). *@
+                <InputTextArea id="script-source" @bind-Value="_form.SourceCode"
+                               class="form-control form-control-sm mono" rows="20"
+                               placeholder="// C# expression body" />
+                <div class="form-text">SHA-256 hash is computed automatically on save. Monaco editor attaches over the textarea on render.</div>
             </div>
         </section>
 
@@ -104,6 +110,24 @@ else
         _loaded = true;
     }
 
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (!firstRender || !_loaded) return;
+        // Inject loader once, then attach over the textarea. Failures are silent — the page
+        // is fully usable via the underlying textarea if Monaco's CDN is unreachable.
+        try
+        {
+            await JS.InvokeVoidAsync("eval", "if (!document.querySelector('script[data-otopcua=monaco-loader]')) { var s=document.createElement('script'); s.src='/_content/ZB.MOM.WW.OtOpcUa.AdminUI/js/monaco-loader.js'; s.dataset.otopcua='monaco-loader'; document.head.appendChild(s); }");
+            // Wait a tick for the loader IIFE to register window.otOpcUaScriptEditor, then attach.
+            await Task.Delay(50);
+            await JS.InvokeVoidAsync("otOpcUaScriptEditor.attach", "script-source");
+        }
+        catch
+        {
+            // Textarea remains the editor — no-op.
+        }
+    }
+
     private async Task SubmitAsync()
     {
         _busy = true; _error = null;