feat(historian): Part 13 time-weighted aggregates on SqlServer + QuestDb (#671)

New AggregateFamily.TimeWeighted serving TimeAverage, TimeAverage2, Total,
Total2 and Interpolative, evaluated by the shared Sql.Common
TimeWeightedAggregator for both SQL backends (identical results by
construction). HistoryAggregateType gains TimeAverage2 + Total2 (appended);
OtOpcUaNodeManager.MapAggregate maps their NodeIds. Gateway's mapper already
refuses unknown defined members => BadAggregateNotSupported per node.

Semantics (server defaults, client AggregateConfiguration ignored):
TreatUncertainAsBad=false, PercentDataBad=PercentDataGood=100,
UseSlopedExtrapolation=false. Sloped for Double/Int64, stepped for Boolean;
a usable sample followed by a Bad one is held up to the outage (AtTime rule);
stepped Uncertain extrapolation past the last sample. TimeAverage/Total use
interpolated bounding (bridge outages); TimeAverage2/Total2 exclude Bad time.
Bounding values: latest usable + latest any before start, first any + first
usable at/after end (four TOP 1 / LIMIT 1 seeks).

CLIENT-VISIBLE: Total on SqlServer/QuestDb was SUM of samples; it is now the
time-weighted integral (TimeAverage x interval seconds), matching Gateway's
Integral. Release note in docs/Historian.md.

Trade-off (deviation from the preferred hybrid pushdown, allowed by the
design): the time-weighted family is NOT pushed down. Each read streams the
window's rows plus the four bounds (SQL Server: one five-result-set batch;
QuestDB: bounds UNION ALL + window select) into the C# evaluator. Network is
O(samples in window), memory O(buckets). Writing the per-segment
interpolation/edge splitting twice in two SQL dialects and keeping them
bit-identical was judged the bigger risk; this also makes the QuestDB
lag/lead spike moot.

Tests: 35 hand-computed TimeWeightedAggregator unit cases (each of 10
implementation mutations goes red); served-aggregate pin 13 -> 17;
conformance sparse fixture (intervals wider and narrower than sample gaps)
+ an outage straddling both window edges (each of the four SQL seeks
disabled in turn goes red); node-manager NodeId mapping test.

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Sql.Common.Tests/ProcessedReadTests.cs

@@ -10,7 +10,11 @@ public sealed class ProcessedReadTests
     [Fact]
     public void Every_enum_member_is_either_served_or_refused()
     {
-        // Thirteen served; anything appended to the enum later falls to the refusal (total default).
-        Enum.GetValues<HistoryAggregateType>().Count(a => AggregateFamilies.FamilyOf(a) is not null).ShouldBe(13);
+        // Seventeen served (#671 added TimeAverage, TimeAverage2, Interpolative and Total2, and moved Total to the
+        // time-weighted family); anything appended to the enum later falls to the refusal (total default).
+        Enum.GetValues<HistoryAggregateType>().Count(a => AggregateFamilies.FamilyOf(a) is not null).ShouldBe(17);
+        Enum.GetValues<HistoryAggregateType>().Where(a => AggregateFamilies.FamilyOf(a) == AggregateFamily.TimeWeighted)
+            .ShouldBe([HistoryAggregateType.Total, HistoryAggregateType.Interpolative, HistoryAggregateType.TimeAverage,
+                HistoryAggregateType.TimeAverage2, HistoryAggregateType.Total2]);
     }
 }