feat(historian): #677 Part 13/SDK reverse anchoring, start-of-data Partial, AggregateConfiguration, IntegralDivisor

- BucketPlan: reverse processed reads anchored at the later time for every
  aggregate: window (end, start], partial interval earliest, results stamped
  with the later edge, latest first (SDK CreateSlice/GetTimestamp/backward
  GetValues). SqlServer adds @bucketAdjustTicks + flips the window predicate;
  QuestDB binds BucketBaseUnixTicks. IndexOf is the C# statement of the math.
- Partial bit on the interval the tag's data starts inside (SDK m_startOfData),
  every aggregate but Average; per-sample reads fetch the earliest sample.
- Node manager: non-default client AggregateConfiguration =>
  BadAggregateConfigurationRejected per node (ServerAggregateConfiguration,
  pinned to the SDK AggregateManager defaults).
- GatewayTagProvisioner sends IntegralDivisor = 1.
- SDK parity oracle (Opc.Ua.Server calculators) in unit + both backends'
  conformance suites, forward and reverse; remaining divergences documented.
- docs/Historian.md + CLAUDE.md release note (client-visible).

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

@@ -5009,6 +5009,8 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
     {
         // OPC UA ProcessingInterval is a Duration in milliseconds — convert once per batch.
         var interval = TimeSpan.FromMilliseconds(details.ProcessingInterval);
+        // #677: a client AggregateConfiguration other than the server defaults is refused per node, never silently ignored.
+        var configurationServable = ServerAggregateConfiguration.IsServable(details.AggregateConfiguration);
         nodesToProcess = AuthorizeHistoryRead(context, nodesToProcess, results, errors);
         WithHistoryReadBatchLimiter(nodesToProcess, results, errors, () =>
         {
@@ -5027,6 +5029,12 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
                     continue;
                 }
 
+                if (!configurationServable)
+                {
+                    errors[handle.Index] = StatusCodes.BadAggregateConfigurationRejected;
+                    continue;
+                }
+
                 // Processed is SINGLE-SHOT (no continuation point). Unlike Raw, ReadProcessedDetails carries
                 // NO client count cap (NumValuesPerNode) — the bucket count is deterministic (window / interval)
                 // and the single-shot backend returns every bucket in one read, so there is no "full page ⇒