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).

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.QuestDb.IntegrationTests/ReadTests.cs

@@ -82,7 +82,8 @@ public sealed class ReadTests(QuestDbFixture fx) : IAsyncLifetime
         foreach (var agg in new[] { HistoryAggregateType.Average, HistoryAggregateType.Start, HistoryAggregateType.MaximumActualTime })
         {
             var s = (await src.ReadProcessedAsync("A", start, end, TimeSpan.Zero, agg, Ct)).Samples.Single();
-            s.StatusCode.ShouldBe(UncertainCalc, agg.ToString());
+            // The data starts (+0) strictly inside the one interval ⇒ Partial on every aggregate but Average (#677).
+            s.StatusCode.ShouldBe(agg == HistoryAggregateType.Average ? UncertainCalc : UncertainCalc | 0x4u, agg.ToString());
         }
         (await src.ReadProcessedAsync("A", start, end, TimeSpan.Zero, HistoryAggregateType.Average, Ct)).Samples.Single().Value.ShouldBe(30d);
         (await src.ReadProcessedAsync("A", start, end, TimeSpan.Zero, HistoryAggregateType.Start, Ct)).Samples.Single().Value.ShouldBe(10d);