fix(historian): #677 review — start-of-data Partial forward-only, bounded/skipped earliest-sample query, wider SDK parity

F1: the SDK applies its m_startOfData Partial rule to forward reads only; ours
now does too (AggregateEvaluator.EvaluateAll + TimeWeightedAggregator). New
reverse late-start parity tests through the SDK oracle (unit) and real SQL
(conformance, both backends).
F2: AggregateEvaluator.NeedsEarliestSample — the earliest-sample query runs
only for forward reads of aggregates other than Average, and is bounded by
the window end (SqlServer < @end, QuestDB ts < $2).
F3: per-sample SDK parity extended to Range, Start, End, Delta, Min/Max
ActualTime and PercentGood/Bad (oracle maps StatusAggregateCalculator);
pre-existing definitional differences masked and marked #680.
Docs: Historian.md Partial/SDK-parity sections, CLAUDE.md bullet.

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.SqlServer/SqlAggregateQueries.cs

@@ -131,12 +131,13 @@ internal static class SqlAggregateQueries
 
     /// <summary>
     ///     The earliest stored sample of the tag (any quality), one row (<c>NULL</c> when none): the start-of-data Partial
-    ///     rule (#677). A <c>MIN</c> over the <c>(TagId, SourceTimeUtc)</c> key — a single seek.
+    ///     rule (#677; forward reads only). A <c>MIN</c> over the <c>(TagId, SourceTimeUtc)</c> key — a single seek — bounded
+    ///     by the window end (a sample at or past it cannot lie inside an interval).
     /// </summary>
     /// <param name="sample">Schema-qualified <c>Sample</c> table name.</param>
     /// <returns>The SQL text.</returns>
     public static string EarliestSample(string sample) =>
-        $"SELECT MIN(SourceTimeUtc) FROM {sample} WHERE TagId = @id;";
+        $"SELECT MIN(SourceTimeUtc) FROM {sample} WHERE TagId = @id AND SourceTimeUtc < @end;";
 
     /// <summary>The <c>s</c> CTE: the window's samples with bucket index and the usable/good flags.</summary>
     private static string Classified(string sample, bool reverse) =>