fix(store-and-forward): resolve StoreAndForward-006,007,008,009 — transactional parked reads, PipeTo, fault-isolated activity events; 002/011/012 deferred

src/ScadaLink.StoreAndForward/StoreAndForwardService.cs

@@ -377,9 +377,34 @@ public class StoreAndForwardService
         return await _storage.GetMessageCountByOriginInstanceAsync(instanceName);
     }
 
+    /// <summary>
+    /// WP-14: Raises the S&amp;F activity notification. StoreAndForward-009: the
+    /// delegate is snapshotted (so a concurrent unsubscribe cannot NRE) and every
+    /// subscriber invocation is wrapped so a slow/throwing subscriber (e.g. the site
+    /// event log) cannot abort the caller. Crucially, a subscriber exception raised
+    /// from <see cref="EnqueueAsync"/> or <c>RetryMessageAsync</c> must NOT be
+    /// misclassified as a transient delivery failure — pre-fix it escaped into the
+    /// delivery try/catch and caused a successfully delivered message to be buffered
+    /// (or its retry count to be bumped). Activity logging is best-effort.
+    /// </summary>
     private void RaiseActivity(string action, StoreAndForwardCategory category, string detail)
     {
-        OnActivity?.Invoke(action, category, detail);
+        var handlers = OnActivity;
+        if (handlers == null) return;
+
+        foreach (var handler in handlers.GetInvocationList().Cast<Action<string, StoreAndForwardCategory, string>>())
+        {
+            try
+            {
+                handler(action, category, detail);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex,
+                    "Store-and-forward activity subscriber threw for action {Action}; ignored",
+                    action);
+            }
+        }
     }
 }