fix(opcua): issue and resume continuation points for event HistoryRead (#669)

A capped events read now pages: the source's truncation flag triggers a
session-bound cursor (time inclusive + tie skip), oversized tie clusters
are paged within via a bounded half-open over-fetch, and release/unknown/
cross-kind points behave as for Raw.

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/HistoryPaging.cs

@@ -31,12 +31,19 @@ namespace ZB.MOM.WW.OtOpcUa.OpcUaServer;
 ///     prior pages and must be dropped from the head of the next page (tie de-dup).
 /// </param>
 /// <param name="NumValuesPerNode">The client's per-page cap; re-applied to every resumed page.</param>
+/// <param name="IsEvents">
+///     <c>true</c> for an EVENT HistoryRead cursor (Gitea #669): <paramref name="Tagname"/> then carries the
+///     registered historian event-source name and the boundary fields are over <c>EventTimeUtc</c>. A cursor
+///     is only ever resumed by the read kind that issued it, so a raw point presented to an events read
+///     (or vice versa) is a <c>BadContinuationPointInvalid</c> miss.
+/// </param>
 internal sealed record HistoryContinuationState(
     string Tagname,
     DateTime NextStartUtc,
     DateTime EndUtc,
     int BoundarySkipCount,
-    uint NumValuesPerNode);
+    uint NumValuesPerNode,
+    bool IsEvents = false);
 
 /// <summary>
 ///     Pure server-side continuation-point paging decisions for the count-capped variable-history arms