perf(historian): batch ingest — one group commit per value burst

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ScriptedAlarms/ScriptedAlarmHostActor.cs

@@ -401,6 +401,18 @@ public sealed class ScriptedAlarmHostActor : ReceiveActor
 
     /// <summary>One batched mux delivery — every item already matched this host's registered interest.
     /// Loops the per-value handler, preserving in-burst order.</summary>
+    /// <remarks>
+    ///     <b>Mid-batch exception policy: unguarded, deliberately.</b> An exception escaping
+    ///     <see cref="OnDependencyChanged"/> drops the remaining items of this burst and restarts the actor
+    ///     — exactly what it already did when the same values arrived as N separate messages (the tail is
+    ///     then lost to the mailbox flush instead of to the loop), so batching changes the blast radius by
+    ///     nothing. Catching per item is deliberately NOT done: the handler is a single
+    ///     <c>IUpstreamValueSource.Push</c> into an in-memory cache, so a throw means the upstream itself is
+    ///     broken and swallowing it would feed the engine a silently truncated burst. Contrast
+    ///     <c>ContinuousHistorizationRecorder.IngestAsync</c>, which DOES catch per item because its
+    ///     per-item step runs value coercion.
+    /// </remarks>
+    /// <param name="msg">The batch of matched dependency values.</param>
     private void OnDependencyBatch(VirtualTagActor.DependencyValueBatch msg)
     {
         var items = msg.Items;