fix(kpihistory)+fix(notificationoutbox)+fix(sitecallaudit)+fix(host): P5-5 — rate-fold interval triple made self-consistent + cross-validated

Defect: the hourly KPI rollup fold (KpiHistoryRepository.FoldHourlyRollupsAsync)
sums every Rate-classified sample recorded in an hour, correct only if each
sample is a non-overlapping delta covering exactly one recorder tick
(KpiHistoryOptions.SampleInterval). That invariant was an unenforced silent
assumption across three independently-owned config keys — SampleInterval,
NotificationOutboxOptions.DeliveredKpiWindow, SiteCallAuditOptions.KpiInterval —
so widening DeliveredKpiWindow to e.g. 15 min would silently over-count the
rollup ~15x.

Robust fix: NotificationOutboxKpiSampleSource and SiteCallAuditKpiSampleSource
now rescale their Rate-classified samples (deliveredLastInterval,
failedLastInterval) by SampleInterval / (DeliveredKpiWindow or KpiInterval)
before recording, so the rollup's per-hour Sum is correct regardless of how
the other two keys are tuned — the live dashboard tile's own cutoff/window is
untouched. Both sources gain a project reference to KpiHistory to read
SampleInterval; no cycle (KpiHistory references only Commons).

Eager cross-validation (defense-in-depth): KpiRateFoldIntervalCrossValidator
(Host, the one composition root referencing all three component projects)
fails boot naming all three config keys when they diverge, protecting the
separate (still-real) invariant that the recorded/charted KPI-history sample
equals the live tile at the same instant — which the rescale trades away
whenever the scale factor isn't 1. Rides KpiHistoryOptions' existing
ValidateOnStart trigger.

Also: NotificationOutboxOptions had no registered validator at all before this
(the gap this task's "whichever options class owns DeliveredKpiWindow" file
scope pointed at) — added NotificationOutboxOptionsValidator mirroring
SiteCallAuditOptionsValidator's positive-duration/count convention, wired with
ValidateOnStart.

Tests: new rescale tests in both sample-source suites prove the fold is
numerically correct at a non-default SampleInterval (30/40 counted over a
15/20-minute window correctly divides down to a 1-minute-tick delta); new
KpiRateFoldIntervalCrossValidatorTests prove divergent config fails with all
three keys named; new NotificationOutboxOptionsValidatorTests. Every new test
proven to fail against the unfixed computation first (temporarily
short-circuited the scale factor / cross-check to the pre-fix behavior,
confirmed failure, restored) — not via git stash (repo-wide, shared across
concurrent worktrees this session) but via file-copy swap.

Full suites green: Host.Tests (527), ConfigurationDatabase.Tests (401),
KpiHistory.Tests (54), NotificationOutbox.Tests (163),
SiteCallAudit.Tests (67).

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Repositories/KpiHistoryRepository.cs

@@ -166,6 +166,19 @@ public sealed class KpiHistoryRepository : IKpiHistoryRepository
             // Per-metric aggregation intent: Rate metrics sum the hour (last-value would
             // discard 59 of 60 intra-hour deltas); Gauge metrics keep the last (latest
             // timestamp) value in the hour. Min/Max/Count preserve the fold's fidelity.
+            //
+            // This Sum is only correct if every sample in the group is a non-overlapping
+            // delta covering exactly one recorder tick (KpiHistoryOptions.SampleInterval).
+            // That invariant used to be an unenforced assumption across three
+            // independently-owned config keys (KpiHistoryOptions.SampleInterval,
+            // NotificationOutboxOptions.DeliveredKpiWindow, SiteCallAuditOptions.KpiInterval)
+            // — widening one silently over/under-counted the rollup (arch-review P5-5, Low).
+            // As of P5-5, NotificationOutboxKpiSampleSource / SiteCallAuditKpiSampleSource
+            // rescale their Rate-classified samples onto SampleInterval before recording, so
+            // this Sum is correct here regardless of how the other two keys are tuned; a
+            // boot-time cross-validator (Host's KpiRateFoldIntervalCrossValidator) still
+            // enforces all three being equal so the recorded/charted samples never silently
+            // diverge from what the live dashboard tile shows at the same instant.
             var aggregation = KpiMetricAggregationCatalog.Resolve(key.Source, key.Metric);
             var value = aggregation == KpiRollupAggregation.Rate
                 ? group.Sum(s => s.Value)