fix(historian): #671 review — raw-row cap, reverse Interpolative, SDK status rule, Partial bit

M1: the time-weighted family (incl. Total, formerly a pushed-down SUM) streams
raw window rows into the C# evaluator. New shared knob
ServerHistorian:MaxTimeWeightedRawRows (default 1,000,000; <=0 unbounded with a
Validate warning) flows through HistorianBackendRegistry into both providers.
The window query is capped at cap+1 (SQL Server TOP (@maxRows), QuestDB LIMIT $4);
one row past the cap throws the new Core.Abstractions
HistoryReadLimitExceededException, which the node manager maps to
BadTooManyOperations for that node. Not counted as a backend health failure;
bound rows are not counted; per-sample aggregates are not capped.

M2: reverse Interpolative is anchored at the later time (Part 13): points at
End - i*interval, emitted latest first. 10:00->09:00 @1h yields 10:00.

L1: Partial bit (0x4, = Opc.Ua.AggregateBits.Partial) on non-Bad results of a
truncated last interval (time-weighted family; per-sample family is a follow-up).

L2/L3: aligned with the SDK AggregateCalculator.GetTimeBasedStatusCode
(decompiled from Opc.Ua.Server 1.5.378.106): TreatUncertainAsBad=false counts
Uncertain time (Uncertain samples, held-into-outage, extrapolation) as Good
time; data but no non-Bad time => generic Bad (0x80000000); BadNoData only
when there is no data at all. Consequence: a live tag's latest interval reads
Good (documented).

L5: release note no longer claims Total matches the Gateway Integral exactly
(AVEVA's divisor is unverified); it notes Total is now evaluated in C# and
subject to the cap.

Tests: unit (reverse Interpolative x3, Partial, Bad vs BadNoData incl. an
open-ended outage, cap helpers, SDK bit oracles); conformance (reverse
Interpolative, raw-row cap at/over/0, bounds not counted, health unaffected);
node manager BadTooManyOperations; options default + warning. Each new
behaviour falsified by mutation (aggregator x9, data-source cap checks on
both backends against the real DBs, node-manager catch).

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.QuestDb/QuestDbHistorianDataSource.cs

@@ -64,6 +64,7 @@ public sealed class QuestDbHistorianDataSource : IHistorianDataSource
     private readonly ILogger _log;
     private readonly TimeProvider _time;
     private readonly HistorianHealthCounters _health = new();
+    private readonly int _maxTimeWeightedRawRows;
 
     /// <summary>Creates the data source over the provider's shared connection, bootstrapper and tag catalog.</summary>
     /// <param name="conn">Connection helper.</param>
@@ -71,10 +72,12 @@ public sealed class QuestDbHistorianDataSource : IHistorianDataSource
     /// <param name="catalog">Tag catalog (reads use only its read-only <see cref="QuestDbTagCatalog.ExistsAsync"/>).</param>
     /// <param name="log">Optional logger.</param>
     /// <param name="timeProvider">Clock for "now" (AtTime beyond the last sample, server timestamps); system by default.</param>
+    /// <param name="maxTimeWeightedRawRows">Raw in-window row cap of one time-weighted read (&lt;= 0 = unbounded).</param>
     internal QuestDbHistorianDataSource(
         QuestDbConnection conn, QuestDbSchemaBootstrapper bootstrap, QuestDbTagCatalog catalog, ILogger? log = null,
-        TimeProvider? timeProvider = null)
+        TimeProvider? timeProvider = null, int maxTimeWeightedRawRows = TimeWeightedAggregator.DefaultMaxWindowRows)
     {
+        _maxTimeWeightedRawRows = maxTimeWeightedRawRows;
         _conn = conn ?? throw new ArgumentNullException(nameof(conn));
         _bootstrap = bootstrap ?? throw new ArgumentNullException(nameof(bootstrap));
         _catalog = catalog ?? throw new ArgumentNullException(nameof(catalog));
@@ -387,6 +390,11 @@ public sealed class QuestDbHistorianDataSource : IHistorianDataSource
             RecordSuccess();
             return new HistoryReadResult(result, ContinuationPoint: null);
         }
+        catch (HistoryReadLimitExceededException)
+        {
+            // A client-request limit (the raw-row cap), not a backend fault: not counted as a failure.
+            throw;
+        }
         catch (Exception ex)
         {
             RecordFailure(ex);
@@ -420,9 +428,16 @@ public sealed class QuestDbHistorianDataSource : IHistorianDataSource
             QuestDbConnection.BindText(cmd, tag);
             QuestDbConnection.BindTimestamp(cmd, plan.StartUtc);
             QuestDbConnection.BindTimestamp(cmd, plan.EndUtc);
+            cmd.Parameters.Add(new NpgsqlParameter
+                { NpgsqlDbType = NpgsqlDbType.Integer, Value = TimeWeightedAggregator.WindowFetchLimit(_maxTimeWeightedRawRows) });
             await using var reader = await cmd.ExecuteReaderAsync(ct).ConfigureAwait(false);
+            long windowRows = 0;
             while (await reader.ReadAsync(ct).ConfigureAwait(false))
+            {
+                // LIMIT $4 = cap + 1: one row past the cap fails the node without reading on.
+                TimeWeightedAggregator.CheckWindowRows(++windowRows, _maxTimeWeightedRawRows, tag);
                 tw.Add(ReadStored(reader, 0));
+            }
         }
         if (bounds[2] is { } anyAfter) tw.Add(anyAfter);
         if (bounds[3] is { } usableAfter) tw.Add(usableAfter);