feat(notif-outbox): carry + persist SourceNode end-to-end via NotificationSubmit

Site: inject INodeIdentityProvider where NotificationSubmit is built; stamp
SourceNode = NodeName at construction.

Central: NotificationOutboxActor.HandleSubmit copies submit.SourceNode onto
the Notification row; the repository INSERT persists it (EF tracked-entity
insert flows it through automatically; raw-SQL extension if not).

After this commit, every Notifications row carries the originating site
node-a/node-b in SourceNode. Existing notifications submitted pre-feature
remain NULL.

src/ScadaLink.NotificationOutbox/NotificationOutboxActor.cs

@@ -957,6 +957,13 @@ public class NotificationOutboxActor : ReceiveActor, IWithTimers
         {
             SourceInstanceId = msg.SourceInstanceId,
             SourceScript = msg.SourceScript,
+            // SourceNode (SourceNode-stamping Task 13): the cluster node on which the
+            // notification was emitted (node-a/node-b for site rows). Stamped by the
+            // emitting site from INodeIdentityProvider and carried, inside the
+            // serialized payload, through the S&F buffer to central. EF tracked-entity
+            // insert flows it through to the Notifications.SourceNode column. Null on
+            // submissions buffered before the field existed.
+            SourceNode = msg.SourceNode,
             // OriginExecutionId (Audit Log #23): the originating script execution's id,
             // carried from the site so the dispatcher can echo it onto NotifyDeliver rows.
             OriginExecutionId = msg.OriginExecutionId,

src/ScadaLink.SiteRuntime/Actors/ScriptExecutionActor.cs

@@ -124,6 +124,13 @@ public class ScriptExecutionActor : ReceiveActor
                 // to the no-emission path (the underlying S&F handoff still
                 // happens and a TrackedOperationId is still returned).
                 ICachedCallTelemetryForwarder? cachedForwarder = null;
+                // SourceNode-stamping (Tasks 13/14): the local node name
+                // resolved from INodeIdentityProvider — node-a/node-b on site
+                // hosts. Null in tests / hosts that haven't registered the
+                // provider, in which case NotificationSubmit.SourceNode and
+                // SiteCallOperational.SourceNode stay null and central
+                // persists the rows with SourceNode NULL.
+                string? sourceNode = null;
 
                 if (serviceProvider != null)
                 {
@@ -136,6 +143,7 @@ public class ScriptExecutionActor : ReceiveActor
                     auditWriter = serviceScope.ServiceProvider.GetService<IAuditWriter>();
                     operationTrackingStore = serviceScope.ServiceProvider.GetService<IOperationTrackingStore>();
                     cachedForwarder = serviceScope.ServiceProvider.GetService<ICachedCallTelemetryForwarder>();
+                    sourceNode = serviceScope.ServiceProvider.GetService<INodeIdentityProvider>()?.NodeName;
                 }
 
                 var context = new ScriptRuntimeContext(
@@ -175,7 +183,13 @@ public class ScriptExecutionActor : ReceiveActor
                     // id for an inbound-API-routed call. The routed script still
                     // mints its own fresh ExecutionId — this records the spawner.
                     // Null for normal (tag-change / timer) runs.
-                    parentExecutionId: parentExecutionId);
+                    parentExecutionId: parentExecutionId,
+                    // SourceNode-stamping (Tasks 13/14): the local node name
+                    // (node-a/node-b on a site) — threaded down so Notify.Send
+                    // and the four cached-call telemetry constructors can stamp
+                    // it onto NotificationSubmit.SourceNode and
+                    // SiteCallOperational.SourceNode respectively.
+                    sourceNode: sourceNode);
 
                 var globals = new ScriptGlobals
                 {

src/ScadaLink.SiteRuntime/Scripts/ScriptRuntimeContext.cs

@@ -71,6 +71,19 @@ public class ScriptRuntimeContext
     /// </summary>
     private readonly string _siteId;
 
+    /// <summary>
+    /// SourceNode-stamping (Task 13/14): the cluster node name supplied by
+    /// <c>INodeIdentityProvider</c> on the local host — <c>node-a</c>/<c>node-b</c>
+    /// for site nodes. Stamped onto <c>NotificationSubmit.SourceNode</c> by
+    /// <see cref="NotifyTarget.Send"/> and onto <c>SiteCallOperational.SourceNode</c>
+    /// by the four <see cref="ExternalSystemHelper"/> / <see cref="DatabaseHelper"/>
+    /// cached-call telemetry construction sites so central can persist it on the
+    /// <c>Notifications</c> / <c>SiteCalls</c> rows. Null when no provider is
+    /// wired (legacy hosts / tests) — the helper construction sites pass null
+    /// through verbatim, leaving the central row's SourceNode as NULL too.
+    /// </summary>
+    private readonly string? _sourceNode;
+
     /// <summary>
     /// Notification Outbox (FU3): identifier of the script currently executing in this
     /// context — stamped onto <c>NotificationSubmit.SourceScript</c> for the central
@@ -162,7 +175,8 @@ public class ScriptRuntimeContext
         IOperationTrackingStore? operationTrackingStore = null,
         ICachedCallTelemetryForwarder? cachedForwarder = null,
         Guid? executionId = null,
-        Guid? parentExecutionId = null)
+        Guid? parentExecutionId = null,
+        string? sourceNode = null)
     {
         _instanceActor = instanceActor;
         _self = self;
@@ -181,6 +195,11 @@ public class ScriptRuntimeContext
         _auditWriter = auditWriter;
         _operationTrackingStore = operationTrackingStore;
         _cachedForwarder = cachedForwarder;
+        // SourceNode-stamping (Task 13/14): the local node name read from
+        // INodeIdentityProvider at the ScriptExecutionActor; null when no
+        // provider was wired so the downstream callsites pass null through
+        // verbatim — leaving central SourceNode as NULL.
+        _sourceNode = sourceNode;
         _executionId = executionId ?? Guid.NewGuid();
         // Audit Log #23 (ParentExecutionId): stored verbatim — no `?? NewGuid()`
         // fallback. A non-routed run legitimately has no parent and stays null.
@@ -335,7 +354,10 @@ public class ScriptRuntimeContext
         _executionId, _auditWriter,
         // Audit Log #23 (ParentExecutionId): the spawning execution's id,
         // threaded alongside _executionId. Null for non-routed runs.
-        _parentExecutionId);
+        _parentExecutionId,
+        // SourceNode-stamping (Task 13): the local node name (node-a/node-b),
+        // threaded so NotifyTarget.Send can stamp it onto NotificationSubmit.
+        _sourceNode);
 
     /// <summary>
     /// Audit Log #23 (M3): site-local tracking-status API for cached operations.
@@ -1328,6 +1350,14 @@ public class ScriptRuntimeContext
         /// </summary>
         private readonly IAuditWriter? _auditWriter;
 
+        /// <summary>
+        /// SourceNode-stamping (Task 13): the cluster node name on which this
+        /// script is executing — <c>node-a</c>/<c>node-b</c>. Stamped onto
+        /// <c>NotificationSubmit.SourceNode</c> by <see cref="NotifyTarget.Send"/>
+        /// so central can persist it on the <c>Notifications</c> row.
+        /// </summary>
+        private readonly string? _sourceNode;
+
         // Parameter ordering: executionId sits immediately after the ILogger,
         // consistent with the other audit-threaded ctors. parentExecutionId is
         // a trailing optional param.
@@ -1341,7 +1371,8 @@ public class ScriptRuntimeContext
             ILogger logger,
             Guid executionId,
             IAuditWriter? auditWriter = null,
-            Guid? parentExecutionId = null)
+            Guid? parentExecutionId = null,
+            string? sourceNode = null)
         {
             _storeAndForward = storeAndForward;
             _siteCommunicationActor = siteCommunicationActor;
@@ -1353,6 +1384,7 @@ public class ScriptRuntimeContext
             _executionId = executionId;
             _auditWriter = auditWriter;
             _parentExecutionId = parentExecutionId;
+            _sourceNode = sourceNode;
         }
 
         /// <summary>
@@ -1370,7 +1402,10 @@ public class ScriptRuntimeContext
                 _auditWriter,
                 // Audit Log #23 (ParentExecutionId): the spawning execution's
                 // id, threaded alongside _executionId. Null for non-routed runs.
-                _parentExecutionId);
+                _parentExecutionId,
+                // SourceNode-stamping (Task 13): the local node name, stamped
+                // onto NotificationSubmit.SourceNode in Send().
+                _sourceNode);
         }
 
         /// <summary>
@@ -1467,6 +1502,15 @@ public class ScriptRuntimeContext
         /// </summary>
         private readonly IAuditWriter? _auditWriter;
 
+        /// <summary>
+        /// SourceNode-stamping (Task 13): the cluster node name on which this
+        /// script is executing (<c>node-a</c>/<c>node-b</c>). Stamped onto the
+        /// <c>NotificationSubmit.SourceNode</c> field in <see cref="Send"/> so
+        /// the central <c>NotificationOutboxActor</c> can persist it on the
+        /// <c>Notifications</c> row.
+        /// </summary>
+        private readonly string? _sourceNode;
+
         internal NotifyTarget(
             string listName,
             StoreAndForwardService? storeAndForward,
@@ -1476,7 +1520,8 @@ public class ScriptRuntimeContext
             ILogger logger,
             Guid executionId,
             IAuditWriter? auditWriter = null,
-            Guid? parentExecutionId = null)
+            Guid? parentExecutionId = null,
+            string? sourceNode = null)
         {
             _listName = listName;
             _storeAndForward = storeAndForward;
@@ -1487,6 +1532,7 @@ public class ScriptRuntimeContext
             _executionId = executionId;
             _auditWriter = auditWriter;
             _parentExecutionId = parentExecutionId;
+            _sourceNode = sourceNode;
         }
 
         /// <summary>
@@ -1539,7 +1585,13 @@ public class ScriptRuntimeContext
                 // for an inbound-API-routed execution, null otherwise. It rides through
                 // the S&F buffer to central, where the dispatcher echoes it onto the
                 // NotifyDeliver rows so the central rows carry the routed run's parent id.
-                OriginParentExecutionId: _parentExecutionId);
+                OriginParentExecutionId: _parentExecutionId,
+                // SourceNode-stamping (Task 13): the cluster node name on which this
+                // notification was emitted (node-a/node-b). Stamped from the local
+                // INodeIdentityProvider via ScriptExecutionActor. Rides inside the
+                // serialized payload through the S&F buffer to central, where
+                // NotificationOutboxActor persists it on the Notifications row.
+                SourceNode: _sourceNode);
 
             var payloadJson = JsonSerializer.Serialize(payload);
 

tests/ScadaLink.NotificationOutbox.Tests/NotificationOutboxActorIngestTests.cs

@@ -42,7 +42,8 @@ public class NotificationOutboxActorIngestTests : TestKit
     private static NotificationSubmit MakeSubmit(
         string? notificationId = null,
         Guid? originExecutionId = null,
-        Guid? originParentExecutionId = null)
+        Guid? originParentExecutionId = null,
+        string? sourceNode = null)
     {
         return new NotificationSubmit(
             NotificationId: notificationId ?? Guid.NewGuid().ToString(),
@@ -54,7 +55,8 @@ public class NotificationOutboxActorIngestTests : TestKit
             SourceScript: "AlarmScript",
             SiteEnqueuedAt: new DateTimeOffset(2026, 5, 19, 8, 30, 0, TimeSpan.Zero),
             OriginExecutionId: originExecutionId,
-            OriginParentExecutionId: originParentExecutionId);
+            OriginParentExecutionId: originParentExecutionId,
+            SourceNode: sourceNode);
     }
 
     [Fact]
@@ -192,4 +194,43 @@ public class NotificationOutboxActorIngestTests : TestKit
         Assert.NotNull(ack.Error);
         Assert.Contains("database unavailable", ack.Error);
     }
+
+    [Fact]
+    public void NotificationSubmit_CopiesSourceNode_OntoPersistedNotification()
+    {
+        // SourceNode-stamping (Task 13): the originating site's node name (node-a/node-b)
+        // rides on the NotificationSubmit and must be persisted on the Notification row so
+        // central observers (KPIs, audit drill-ins, ops dashboards) can see which node
+        // emitted the notification.
+        _repository.InsertIfNotExistsAsync(Arg.Any<Notification>(), Arg.Any<CancellationToken>())
+            .Returns(true);
+        var submit = MakeSubmit(sourceNode: "node-a");
+        var actor = CreateActor();
+
+        actor.Tell(submit, TestActor);
+
+        ExpectMsg<NotificationSubmitAck>();
+        _repository.Received(1).InsertIfNotExistsAsync(
+            Arg.Is<Notification>(n => n.SourceNode == "node-a"),
+            Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public void NotificationSubmit_NullSourceNode_PersistsNull()
+    {
+        // Submissions from a host that didn't wire INodeIdentityProvider, or from
+        // pre-SourceNode-stamping clients, carry null SourceNode — the central row must
+        // persist NULL rather than fall back to a placeholder.
+        _repository.InsertIfNotExistsAsync(Arg.Any<Notification>(), Arg.Any<CancellationToken>())
+            .Returns(true);
+        var submit = MakeSubmit(sourceNode: null);
+        var actor = CreateActor();
+
+        actor.Tell(submit, TestActor);
+
+        ExpectMsg<NotificationSubmitAck>();
+        _repository.Received(1).InsertIfNotExistsAsync(
+            Arg.Is<Notification>(n => n.SourceNode == null),
+            Arg.Any<CancellationToken>());
+    }
 }

tests/ScadaLink.SiteRuntime.Tests/Scripts/NotifyHelperTests.cs

@@ -62,7 +62,8 @@ public class NotifyHelperTests : TestKit, IAsyncLifetime, IDisposable
         IActorRef siteCommunicationActor,
         string? sourceScript = null,
         Guid? executionId = null,
-        Guid? parentExecutionId = null)
+        Guid? parentExecutionId = null,
+        string? sourceNode = null)
     {
         return new ScriptRuntimeContext.NotifyHelper(
             _saf,
@@ -74,7 +75,8 @@ public class NotifyHelperTests : TestKit, IAsyncLifetime, IDisposable
             NullLogger.Instance,
             executionId ?? Guid.NewGuid(),
             auditWriter: null,
-            parentExecutionId: parentExecutionId);
+            parentExecutionId: parentExecutionId,
+            sourceNode: sourceNode);
     }
 
     [Fact]
@@ -197,6 +199,45 @@ public class NotifyHelperTests : TestKit, IAsyncLifetime, IDisposable
         Assert.Null(payload!.OriginParentExecutionId);
     }
 
+    [Fact]
+    public async Task Send_StampsSourceNode_OnTheNotificationSubmitPayload()
+    {
+        // SourceNode-stamping (Task 13): when the helper is wired with the
+        // local INodeIdentityProvider's NodeName, Notify.Send must stamp it
+        // onto the NotificationSubmit so it rides inside the serialized S&F
+        // payload to central, where NotificationOutboxActor persists it on
+        // the Notifications row.
+        var commProbe = CreateTestProbe();
+        var notify = CreateHelper(commProbe.Ref, sourceNode: "node-a");
+
+        var notificationId = await notify.To("Operators").Send("Pump alarm", "Pump 3 tripped");
+
+        var buffered = await _saf.GetMessageByIdAsync(notificationId);
+        Assert.NotNull(buffered);
+        var payload = JsonSerializer.Deserialize<NotificationSubmit>(buffered!.PayloadJson);
+        Assert.NotNull(payload);
+        Assert.Equal("node-a", payload!.SourceNode);
+    }
+
+    [Fact]
+    public async Task Send_NoNodeIdentity_LeavesSourceNodeNull()
+    {
+        // Hosts that don't wire INodeIdentityProvider (legacy / tests) pass
+        // null through. The NotificationSubmit payload's SourceNode stays
+        // null so the central Notifications row persists NULL rather than
+        // falling back to a placeholder.
+        var commProbe = CreateTestProbe();
+        var notify = CreateHelper(commProbe.Ref, sourceNode: null);
+
+        var notificationId = await notify.To("Operators").Send("Pump alarm", "Pump 3 tripped");
+
+        var buffered = await _saf.GetMessageByIdAsync(notificationId);
+        Assert.NotNull(buffered);
+        var payload = JsonSerializer.Deserialize<NotificationSubmit>(buffered!.PayloadJson);
+        Assert.NotNull(payload);
+        Assert.Null(payload!.SourceNode);
+    }
+
     [Fact]
     public async Task Send_WhenHelperHasNoSourceScript_LeavesSourceScriptNull()
     {