feat(historian): #691 HistoryRead-Raw ReturnBounds — Part 11 bounding values on every backend

The node manager composes the start/end bounds from each backend's existing raw
reads (one authority, HistoryBounds): at-or-before = a capped reverse read
(native, or ReverseRawReader's walk-back on a forward-only backend — never
AVEVA's synthetic boundary row), at-or-after = a capped forward read. Bounds
count toward NumValuesPerNode, the start bound leads the first page, the end
bound ends the last (carried in the continuation point). Missing bound =
Bad_BoundNotFound (null, at the bound time; one-sided reads ±1 s from the
previous value, Table 1 footnotes a/b). A modified read with ReturnBounds is
Bad_InvalidArgument (Part 11 6.5.3.3).

The .NET SDK's ReadRawModifiedDetails defaults ReturnBounds to TRUE; the
existing tests built details without setting it and now set it false.
Oracle: every row of Part 11 Table 1 over three backend shapes, plus paging
concatenation, ties, Bad bounds, microsecond truncation; conformance pins the
lookup primitives on SqlServer + QuestDB.

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerHistoryReadModifiedTests.cs

@@ -271,7 +271,7 @@ public sealed class NodeManagerHistoryReadModifiedTests : IDisposable
         var results = new List<SdkHistoryReadResult> { null! };
         var errors = new List<ServiceResult> { null! };
         nm.HistoryRead(context,
-            new ReadRawModifiedDetails { StartTime = start, EndTime = end, NumValuesPerNode = max, IsReadModified = modified },
+            new ReadRawModifiedDetails { ReturnBounds = false, StartTime = start, EndTime = end, NumValuesPerNode = max, IsReadModified = modified },
             TimestampsToReturn.Both, false,
             new List<HistoryReadValueId> { new() { NodeId = node, ContinuationPoint = cp } }, results, errors);