feat(ui): add Node column + filter to NotificationOutbox grid

src/ScadaLink.Commons/Messages/Notification/NotificationOutboxQueries.cs

@@ -17,7 +17,8 @@ public record NotificationOutboxQueryRequest(
     DateTimeOffset? From,
     DateTimeOffset? To,
     int PageNumber,
-    int PageSize);
+    int PageSize,
+    string? SourceNodeFilter = null);
 
 /// <summary>
 /// A single notification row summarised for outbox UI display.
@@ -34,7 +35,8 @@ public record NotificationSummary(
     string? SourceInstanceId,
     DateTimeOffset CreatedAt,
     DateTimeOffset? DeliveredAt,
-    bool IsStuck);
+    bool IsStuck,
+    string? SourceNode = null);
 
 /// <summary>
 /// Central -> Outbox UI: paginated response for a <see cref="NotificationOutboxQueryRequest"/>.

src/ScadaLink.Commons/Types/Notifications/NotificationOutboxFilter.cs

@@ -18,6 +18,11 @@ namespace ScadaLink.Commons.Types.Notifications;
 /// <param name="StuckCutoff">Rows with <c>CreatedAt</c> older than this count as stuck.</param>
 /// <param name="From">Inclusive lower bound on <c>CreatedAt</c>.</param>
 /// <param name="To">Inclusive upper bound on <c>CreatedAt</c>.</param>
+/// <param name="SourceNode">
+/// Restrict to notifications originating at a specific cluster node (e.g.
+/// <c>"central-a"</c>, <c>"site-plant-a-node-a"</c>). Exact match; <c>null</c>
+/// means "do not constrain".
+/// </param>
 public record NotificationOutboxFilter(
     NotificationStatus? Status = null,
     NotificationType? Type = null,
@@ -27,4 +32,5 @@ public record NotificationOutboxFilter(
     bool StuckOnly = false,
     DateTimeOffset? StuckCutoff = null,
     DateTimeOffset? From = null,
-    DateTimeOffset? To = null);
+    DateTimeOffset? To = null,
+    string? SourceNode = null);