docs(r2-06): note WriteLiveValues Quality is a documented-dead input (0.2.0 C-002); keep 192 populated (06/C-7)

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/ContinuousHistorizationRecorder.cs

@@ -41,7 +41,14 @@ namespace ZB.MOM.WW.OtOpcUa.Runtime.Historian;
 public sealed class ContinuousHistorizationRecorder : ReceiveActor, IWithTimers
 {
     /// <summary>OPC-DA quality byte recorded for mux-fanned values (the mux drops quality; driver-published
-    /// values are Good by the same convention the scripted-alarm host applies).</summary>
+    /// values are Good by the same convention the scripted-alarm host applies).
+    /// <para>
+    ///     Note (archreview 06/C-7): the historian gateway's <c>WriteLiveValues</c> SQL path <b>discards</b>
+    ///     quality (server-managed column, 0.2.0 Contracts C-002 — see
+    ///     <c>GatewayHistorianValueWriter</c>'s remarks). This constant is therefore what a future
+    ///     quality-honoring gateway path <em>would</em> receive; capturing real per-node quality here will
+    ///     NOT persist until the gateway honors the field.
+    /// </para></summary>
     public const ushort GoodQuality = 192;
 
     private const string DrainTimerKey = "drain";