docs(opcuaclient): #657 review — correct stale rebuild comment, note cold-host residual

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/OpcUaClientDriver.cs

@@ -1887,9 +1887,10 @@ public sealed class OpcUaClientDriver : IDriver, ITagDiscovery, IReadable, IWrit
 
     /// <summary>
     ///     #619 re-review: open (or re-open) the host's alarm subscription over <paramref name="sourceNodeIds"/>.
-    ///     A CHANGED set means the host rebuilt its address space (an alarm-bearing delta always does), recreating
-    ///     every condition node inactive+acked — so every last-told state is forgotten and the post-subscribe
-    ///     ConditionRefresh re-reports from that default. The SAME set (a reinit / reconnect re-subscribe) keeps
+    ///     A CHANGED set means the host applied an alarm-bearing delta, so every last-told state is forgotten and the
+    ///     post-subscribe ConditionRefresh re-reports as first sight. Since #641 a rebuild KEEPS native condition state,
+    ///     so the host may hold ANY state here — which is why first sight is flagged (#656/#657) rather than assuming
+    ///     an inactive+acked default. The SAME set (a reinit / reconnect re-subscribe) keeps
     ///     them, so the refresh copy of an already-reported state emits nothing. Ack targets of refs no longer
     ///     subscribed are pruned either way.
     /// </summary>