Merge ph-T6 (pluggable historian)

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

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

@@ -0,0 +1,15 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Historian;
+
+/// <summary>
+///     DI carrier for the optional <see cref="IHistorianDataUpdater"/> the selected historian backend supplies.
+///     A holder (rather than a nullable registration) lets "this backend cannot modify history" be registered
+///     explicitly as <see cref="None"/>, so consumers resolve one type and branch on <see cref="Updater"/>.
+/// </summary>
+/// <param name="Updater">The backend's updater, or <c>null</c> when HistoryUpdate is unsupported.</param>
+public sealed record HistorianUpdaterHolder(IHistorianDataUpdater? Updater)
+{
+    /// <summary>No updater: every HistoryUpdate is reported unsupported.</summary>
+    public static readonly HistorianUpdaterHolder None = new((IHistorianDataUpdater?)null);
+}