Docs audit — fill gaps so the top-level docs/ reference matches shipped code

Audit of docs/ against src/ surfaced shipped features without current-reference
coverage (FOCAS CLI, Core.Scripting+VirtualTags, Core.ScriptedAlarms,
Core.AlarmHistorian), an out-of-date driver count + capability matrix, ADR-002's
virtual-tag dispatch not reflected in data-path docs, broken cross-references,
and OpcUaServerReqs declaring OPC-020..022 that were never scoped. This commit
closes all of those so operators + integrators can stay inside docs/ without
falling back to v2/implementation/.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/HistoricalDataAccess.md

@@ -22,6 +22,12 @@ Supporting DTOs live alongside the interface in `Core.Abstractions`:
 - `HistoricalEvent(EventId, SourceName?, EventTimeUtc, ReceivedTimeUtc, Message?, Severity)`
 - `HistoricalEventsResult(IReadOnlyList<HistoricalEvent> Events, byte[]? ContinuationPoint)`
 
+## Alarm event history vs. `IHistoryProvider`
+
+`IHistoryProvider.ReadEventsAsync` is the **pull** path: an OPC UA client calls `HistoryReadEvents` against a notifier node and the driver walks its own backend event store to satisfy the request. The Galaxy driver's implementation reads from AVEVA Historian's event schema via `aahClientManaged`; every other driver leaves the default `NotSupportedException` in place.
+
+There is also a separate **push** path for persisting alarm transitions from any `IAlarmSource` (and the Phase 7 scripted-alarm engine) into a durable event log, independent of any client HistoryRead call. That path is covered by `IAlarmHistorianSink` + `SqliteStoreAndForwardSink` in `src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/` and is documented in [AlarmTracking.md#alarm-historian-sink](AlarmTracking.md#alarm-historian-sink). The two paths are complementary — the sink populates an external historian's alarm schema; `ReadEventsAsync` reads from whatever event store the driver owns — and share neither interface nor dispatch.
+
 ## Dispatch through `CapabilityInvoker`
 
 All four HistoryRead surfaces are wrapped by `CapabilityInvoker` (`Core/Resilience/CapabilityInvoker.cs`) with `DriverCapability.HistoryRead`. The Polly pipeline keyed on `(DriverInstanceId, HostName, DriverCapability.HistoryRead)` provides timeout, circuit-breaker, and bulkhead defaults per the driver's stability tier (see [docs/v2/driver-stability.md](v2/driver-stability.md)).