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"/>.