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/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.SqlServer/SqlServerHistorianDataSource.cs

@@ -363,6 +363,12 @@ public sealed class SqlServerHistorianDataSource : IHistorianDataSource
     /// <inheritdoc />
     public IReadOnlySet<HistoryAggregateType> SupportedAggregates => AggregateFamilies.Served;
 
+    /// <inheritdoc />
+    // Data + events; every sample row stores ServerTimeUtc (written by the recorder / HistoryUpdate) and a raw read
+    // returns it (lmxopcua#881).
+    public HistorianReadCapabilities ReadCapabilities =>
+        HistorianReadCapabilities.Data | HistorianReadCapabilities.Events | HistorianReadCapabilities.ServerTimestamps;
+
 
     // <remarks>
     //     <c>[start, end)</c> by <c>EventTimeUtc</c> (a reversed window is swapped), ordered by