fix(central-ui): resolve CentralUI-006 — push-based deployment status via IDeploymentStatusNotifier, remove 10s polling timer

src/ScadaLink.CentralUI/Components/Pages/Deployment/Deployments.razor

@@ -8,6 +8,7 @@
 @inject IDeploymentManagerRepository DeploymentManagerRepository
 @inject ITemplateEngineRepository TemplateEngineRepository
 @inject ScadaLink.CentralUI.Auth.SiteScopeService SiteScope
+@inject ScadaLink.DeploymentManager.IDeploymentStatusNotifier DeploymentStatusNotifier
 @implements IDisposable
 
 <div class="container-fluid mt-3">
@@ -196,47 +197,42 @@
     private Dictionary<int, string> _instanceNames = new();
     private bool _loading = true;
     private string? _errorMessage;
-    private Timer? _refreshTimer;
     private bool _autoRefresh = true;
     private readonly HashSet<string> _expandedErrors = new();
 
     private int _currentPage = 1;
     private int _totalPages;
     private const int PageSize = 25;
-    private static readonly TimeSpan RefreshInterval = TimeSpan.FromSeconds(10);
+
+    // CentralUI-006: deployment status updates are push-based, not polled.
+    // DeploymentManager raises IDeploymentStatusNotifier.StatusChanged on every
+    // deployment-record status write; this page subscribes to it and reloads,
+    // and Blazor Server pushes the re-render to the browser over its SignalR
+    // circuit — satisfying the design's "no polling required" requirement.
+    // The notifier event is raised on the DeploymentManager service thread, so
+    // the handler marshals onto the renderer via InvokeAsync.
 
     protected override async Task OnInitializedAsync()
     {
         await LoadDataAsync();
-        StartTimer();
+        DeploymentStatusNotifier.StatusChanged += OnDeploymentStatusChanged;
     }
 
-    private void StartTimer()
+    private void OnDeploymentStatusChanged(ScadaLink.DeploymentManager.DeploymentStatusChange change)
     {
-        _refreshTimer?.Dispose();
-        _refreshTimer = new Timer(_ =>
+        if (!_autoRefresh) return;
+        _ = InvokeAsync(async () =>
         {
-            InvokeAsync(async () =>
-            {
-                if (!_autoRefresh) return;
-                await LoadDataAsync();
-                StateHasChanged();
-            });
-        }, null, RefreshInterval, RefreshInterval);
+            await LoadDataAsync();
+            StateHasChanged();
+        });
     }
 
     private void ToggleAutoRefresh()
     {
+        // When paused, incoming push notifications are ignored; "Refresh" still
+        // forces a manual reload. No timer is involved either way.
         _autoRefresh = !_autoRefresh;
-        if (_autoRefresh)
-        {
-            StartTimer();
-        }
-        else
-        {
-            _refreshTimer?.Dispose();
-            _refreshTimer = null;
-        }
     }
 
     private bool IsErrorExpanded(string deploymentId) => _expandedErrors.Contains(deploymentId);
@@ -320,6 +316,8 @@
 
     public void Dispose()
     {
-        _refreshTimer?.Dispose();
+        // Unsubscribe so a status change after the circuit is gone does not
+        // touch a disposed component (the notifier is a process singleton).
+        DeploymentStatusNotifier.StatusChanged -= OnDeploymentStatusChanged;
     }
 }