perf(comms): alarms-only seed, capped buffers, at-least-once audit pull

src/ZB.MOM.WW.ScadaBridge.Commons/Messages/DebugView/DebugSnapshotRequest.cs

@@ -1,5 +1,19 @@
 namespace ZB.MOM.WW.ScadaBridge.Commons.Messages.DebugView;
 
+/// <summary>
+/// Asks one instance for a point-in-time <see cref="DebugViewSnapshot"/>.
+/// </summary>
+/// <param name="InstanceUniqueName">Unique name of the instance to snapshot.</param>
+/// <param name="CorrelationId">Correlation id echoed on the reply.</param>
+/// <param name="AlarmsOnly">
+/// When <c>true</c> the site builds ONLY the alarm half of the snapshot and returns an
+/// empty <see cref="DebugViewSnapshot.AttributeValues"/> list (wire efficiency, WP2.3).
+/// Set by the central per-site live alarm cache, whose seed/reconcile fan-out discards
+/// every attribute row anyway. Defaults to <c>false</c> so the Debug View and every other
+/// caller keep the full snapshot; additive on the wire
+/// (<c>DebugSnapshotRequestDto.alarms_only</c>, field 3).
+/// </param>
 public record DebugSnapshotRequest(
     string InstanceUniqueName,
-    string CorrelationId);
+    string CorrelationId,
+    bool AlarmsOnly = false);