fix(history): advertise HistoryServerCapabilities from the wired backend (#881)

Every Boolean under Server/ServerCapabilities/HistoryServerCapabilities read
false (the SDK default) even though data and event history were served, so a
spec-following client skipped HistoryRead entirely.

Each backend now declares what it serves through its own interface:
- IHistorianDataSource.ReadCapabilities (Data / Events / ServerTimestamps):
  Gateway Data|Events; SqlServer + QuestDb add ServerTimestamps (they store
  ServerTimeUtc, the Gateway stamps read time); Null declares None. A
  reflection guard requires every production source to declare it itself.
- IHistorianDataUpdater.Capabilities (required member): SqlServer and QuestDb
  declare Insert/Replace/Update/DeleteRaw/DeleteAtTime; the Gateway provider
  has no updater.

The node manager writes the flags on every source/updater assignment
(AdvertisedHistoryCapabilities), and the same declarations drive dispatch:
an update the updater does not declare is BadHistoryOperationUnsupported
without reaching it, the HistoryWrite AccessLevel bit follows a non-empty
declaration, and event-history notifier promotion follows the Events flag.
Event and annotation update flags stay false (nothing dispatches them).

Tests: booted-server wire test per backend + Null + a SqlServer->Gateway
rewire pairing on one session; dispatch gating unit test; the #801 live
gate now asserts the Gateway flags (not run here).

Claude-Session: https://claude.ai/code/session_01GT67ACmpMR7b9LGRPLijMi

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/Historian/HistoryCapabilities.cs

@@ -0,0 +1,57 @@
+namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+/// <summary>
+///     What a historian backend serves for OPC UA HistoryRead — declared by every <see cref="IHistorianDataSource"/>
+///     (<see cref="IHistorianDataSource.ReadCapabilities"/>) and advertised by the server under
+///     <c>Server/ServerCapabilities/HistoryServerCapabilities</c> (lmxopcua#881).
+/// </summary>
+[Flags]
+public enum HistorianReadCapabilities
+{
+    /// <summary>No history is served (the Null source).</summary>
+    None = 0,
+
+    /// <summary>Data history (raw / modified / processed / at-time) — <c>AccessHistoryDataCapability</c>.</summary>
+    Data = 1,
+
+    /// <summary>Event history on notifier folders — <c>AccessHistoryEventsCapability</c>.</summary>
+    Events = 2,
+
+    /// <summary>
+    ///     The backend stores each sample's server timestamp and returns it on a raw read, rather than stamping the read
+    ///     time — <c>ServerTimestampSupported</c> (Part 11 §5.4.2).
+    /// </summary>
+    ServerTimestamps = 4,
+}
+
+/// <summary>
+///     Which HistoryUpdate operations a <see cref="IHistorianDataUpdater"/> performs — declared by the updater itself
+///     (<see cref="IHistorianDataUpdater.Capabilities"/>). The server both advertises these under
+///     <c>HistoryServerCapabilities</c> and refuses an undeclared operation with <c>BadHistoryOperationUnsupported</c>,
+///     so the advertisement cannot drift from dispatch (lmxopcua#881). There are no event / annotation members: the
+///     server dispatches no event or annotation updates to any backend.
+/// </summary>
+[Flags]
+public enum HistoryUpdateCapabilities
+{
+    /// <summary>No update operation.</summary>
+    None = 0,
+
+    /// <summary><c>UpdateDataDetails</c> with <c>PerformInsertReplace = Insert</c> — <c>InsertDataCapability</c>.</summary>
+    InsertData = 1,
+
+    /// <summary><c>UpdateDataDetails</c> with <c>PerformInsertReplace = Replace</c> — <c>ReplaceDataCapability</c>.</summary>
+    ReplaceData = 2,
+
+    /// <summary><c>UpdateDataDetails</c> with <c>PerformInsertReplace = Update</c> — <c>UpdateDataCapability</c>.</summary>
+    UpdateData = 4,
+
+    /// <summary><c>DeleteRawModifiedDetails</c> with <c>IsDeleteModified = false</c> — <c>DeleteRawCapability</c>.</summary>
+    DeleteRaw = 8,
+
+    /// <summary><c>DeleteAtTimeDetails</c> — <c>DeleteAtTimeCapability</c>.</summary>
+    DeleteAtTime = 16,
+
+    /// <summary>Every data update the server can dispatch.</summary>
+    AllData = InsertData | ReplaceData | UpdateData | DeleteRaw | DeleteAtTime,
+}

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/Historian/IHistorianDataSource.cs

@@ -246,6 +246,19 @@ public interface IHistorianDataSource : IDisposable
     /// </remarks>
     IReadOnlySet<HistoryAggregateType> SupportedAggregates => HistoryAggregateTypes.All;
 
+    /// <summary>
+    ///     What this backend serves for HistoryRead — the authority for the <c>AccessHistoryDataCapability</c>,
+    ///     <c>AccessHistoryEventsCapability</c> and <c>ServerTimestampSupported</c> flags the server advertises under
+    ///     <c>HistoryServerCapabilities</c>, and (<see cref="HistorianReadCapabilities.Events"/>) for whether notifier folders
+    ///     carry the <c>HistoryRead</c> EventNotifier bit and accept HistoryRead-Events (lmxopcua#881).
+    /// </summary>
+    /// <remarks>
+    ///     The default (<see cref="HistorianReadCapabilities.Data"/> | <see cref="HistorianReadCapabilities.Events"/>) keeps a
+    ///     test fake or out-of-tree source serving as before. Every PRODUCTION backend declares it itself (a reflection
+    ///     guard pins that); the Null source declares <see cref="HistorianReadCapabilities.None"/>.
+    /// </remarks>
+    HistorianReadCapabilities ReadCapabilities => HistorianReadCapabilities.Data | HistorianReadCapabilities.Events;
+
     /// <summary>
     ///     Read modified-value history — OPC UA HistoryReadRaw with <c>IsReadModified = true</c> (Part 11):
     ///     every modification a HistoryUpdate applied to the tag inside the window, each carrying the PRIOR value.

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/Historian/IHistorianDataUpdater.cs

@@ -32,6 +32,15 @@ public enum HistoryUpdateMode
 /// </remarks>
 public interface IHistorianDataUpdater
 {
+    /// <summary>
+    ///     The update operations this backend performs — declared by the backend itself (no default, so it cannot be
+    ///     forgotten). The server advertises exactly these under <c>HistoryServerCapabilities</c>
+    ///     (Insert/Replace/UpdateData, DeleteRaw, DeleteAtTime) and answers an operation outside the set with
+    ///     <c>BadHistoryOperationUnsupported</c> without calling the backend (lmxopcua#881). Read when the updater is
+    ///     wired and on every update, so it must be cheap and stable.
+    /// </summary>
+    HistoryUpdateCapabilities Capabilities { get; }
+
     /// <summary>Inserts, replaces or upserts samples for one tag.</summary>
     /// <param name="tag">Historian tag name.</param>
     /// <param name="mode">Update mode.</param>

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/Historian/NullHistorianDataSource.cs

@@ -87,6 +87,11 @@ public sealed class NullHistorianDataSource : IHistorianDataSource
     // historian misled capability discovery. Raw / AtTime / Events reads still return the empty GoodNoData result.
     public IReadOnlySet<HistoryAggregateType> SupportedAggregates => HistoryAggregateTypes.None;
 
+    /// <inheritdoc />
+    // None: no history is served, so HistoryServerCapabilities advertises no data / event access (lmxopcua#881) and no
+    // folder is promoted to an event-history notifier.
+    public HistorianReadCapabilities ReadCapabilities => HistorianReadCapabilities.None;
+
     /// <inheritdoc />
     public HistorianHealthSnapshot GetHealthSnapshot() => new(
         TotalQueries: 0,