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

tests/ScadaLink.DeploymentManager.Tests/ServiceCollectionExtensionsTests.cs

@@ -56,4 +56,25 @@ public class ServiceCollectionExtensionsTests
     {
         Assert.Equal("ScadaLink:DeploymentManager", ServiceCollectionExtensions.OptionsSection);
     }
+
+    // CentralUI-006: the deployment-status notifier must be a singleton so the
+    // scoped DeploymentService and the Central UI's scoped Blazor page share
+    // one instance — without that, a push notification raised by the service
+    // would never reach the page's subscription.
+    [Fact]
+    public void AddDeploymentManager_RegistersDeploymentStatusNotifier_AsSingleton()
+    {
+        var services = new ServiceCollection();
+        services.AddLogging();
+        services.AddDeploymentManager();
+
+        using var provider = services.BuildServiceProvider();
+
+        var fromRoot = provider.GetRequiredService<IDeploymentStatusNotifier>();
+        using var scope = provider.CreateScope();
+        var fromScope = scope.ServiceProvider.GetRequiredService<IDeploymentStatusNotifier>();
+
+        Assert.IsType<DeploymentStatusNotifier>(fromRoot);
+        Assert.Same(fromRoot, fromScope);
+    }
 }