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

src/ScadaLink.DeploymentManager/IDeploymentStatusNotifier.cs

@@ -0,0 +1,49 @@
+using ScadaLink.Commons.Types.Enums;
+
+namespace ScadaLink.DeploymentManager;
+
+/// <summary>
+/// Payload describing a single deployment-record status change. Kept small —
+/// just the deployment identity, the owning instance, and the new status — so
+/// it is cheap to raise on the hot path and cheap for subscribers to handle.
+/// </summary>
+/// <param name="DeploymentId">The unique deployment ID whose status changed.</param>
+/// <param name="InstanceId">The instance the deployment record belongs to.</param>
+/// <param name="Status">The status the deployment record was just written with.</param>
+public readonly record struct DeploymentStatusChange(
+    string DeploymentId,
+    int InstanceId,
+    DeploymentStatus Status);
+
+/// <summary>
+/// CentralUI-006: push-based deployment-status change notification.
+///
+/// The design (Component-CentralUI "Real-Time Updates") requires deployment
+/// status transitions to push to the UI immediately via SignalR, with no
+/// polling. <see cref="DeploymentService"/> raises <see cref="StatusChanged"/>
+/// whenever it writes a <see cref="Commons.Entities.Deployment.DeploymentRecord"/>
+/// status; the Central UI's deployment-status page subscribes to it and
+/// re-renders over its existing Blazor Server SignalR circuit.
+///
+/// Registered as a DI singleton (see <see cref="ServiceCollectionExtensions.AddDeploymentManager"/>)
+/// so the scoped <see cref="DeploymentService"/> and the Blazor circuit's
+/// scoped page component share the same instance — both run in the same
+/// central Host process.
+/// </summary>
+public interface IDeploymentStatusNotifier
+{
+    /// <summary>
+    /// Raised after a deployment record's status has been written. Handlers run
+    /// synchronously on the caller's thread; subscribers must not block and
+    /// should marshal any UI work onto their own dispatcher.
+    /// </summary>
+    event Action<DeploymentStatusChange>? StatusChanged;
+
+    /// <summary>
+    /// Raises <see cref="StatusChanged"/>. Called by <see cref="DeploymentService"/>
+    /// at every point a deployment record's status is persisted. A throwing
+    /// subscriber must not break the deployment pipeline, so handler exceptions
+    /// are swallowed by the implementation.
+    /// </summary>
+    void NotifyStatusChanged(DeploymentStatusChange change);
+}