docs(historian-gateway): document gateway backend, config keys, EnsureTags hook, known gates; retire Wonderware from docs

HistorianGateway is now the sole historian backend (read + alarm SendEvent +
continuous WriteLiveValues). Document the final state and retire the Wonderware
sidecar from the docs/config/labels:

- CLAUDE.md: rewrite the Historian section — ServerHistorian /
  ContinuousHistorization / AlarmHistorian config keys, the IHistorianProvisioning
  EnsureTags hook, the GatewayAlarmHistorianWriter SendEvent path + ReadEvents
  dependency on gateway RuntimeDb:EventReadsEnabled=true, gateway-side
  prerequisites (RuntimeDb flags + historian:read/write/tags:write scopes),
  migration note, and two KNOWN-LIMITATION callouts (live-validation gate +
  empty historized-ref-set recorder follow-on).
- appsettings.json: fix the stale ServerHistorian block (Host/Port/SharedSecret/
  ServerCertThumbprint -> Endpoint/ApiKey/UseTls/AllowUntrustedServerCertificate/
  CaCertificatePath/CallTimeout, keep MaxTieClusterOverfetch); add a disabled
  ContinuousHistorization block; prune the orphaned Wonderware keys from
  AlarmHistorian (keep the SQLite knobs). ApiKey env-supplied via
  ServerHistorian__ApiKey (commented; valid strict JSON via _comment keys).
- README.md + docs (Historian.md, AlarmHistorian.md, Configuration.md,
  ServiceHosting.md, DriverLifecycle.md, drivers/README.md, Uns.md, VirtualTags.md,
  AlarmTracking.md, Client.UI.md, README.md, TestConnectProbes.md): retire the
  Wonderware historian backend from current-backend descriptions; fix the stale
  ServerHistorian/AlarmHistorian config tables (now gateway shape); convert
  drivers/Historian.Wonderware.md to a retired stub pointing at the gateway.
- Source/UI labels (descriptive text only, no behavior change):
  OtOpcUaServerHostedService.cs, HistoryPaging.cs, OtOpcUaSdkServer.cs,
  HistorianAdapterActor.cs, VirtualTagModal.razor, ScriptedAlarmModal.razor,
  AlarmsHistorian.razor now name the HistorianGateway backend.

Build clean (0 errors); AdminUI.Tests green (514 passed).

Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii

docs/Uns.md

@@ -120,14 +120,15 @@ drivers:
 | TwinCAT | Symbol path, data type, etc. |
 | FOCAS | PMC address, data type, etc. |
 | **OpcUaClient** | `FullName` (the remote OPC UA node id string) |
-| **Historian.Wonderware** | `FullName` (the Wonderware tagname to read) |
 
-**OpcUaClient** and **Historian.Wonderware** were previously raw-JSON
-fallback only; they now have first-class typed editors that expose a single
-`FullName` field (PascalCase JSON key, consistent with the Galaxy editor
-convention). Both are registered in `TagConfigEditorMap` and
-`TagConfigValidator`; unknown keys in the stored JSON blob are preserved on
-round-trip.
+**OpcUaClient** was previously raw-JSON fallback only; it now has a first-class
+typed editor that exposes a single `FullName` field (PascalCase JSON key,
+consistent with the Galaxy editor convention). It is registered in
+`TagConfigEditorMap` and `TagConfigValidator`; unknown keys in the stored JSON
+blob are preserved on round-trip.
+
+> The historian backend is the external HistorianGateway (no OtOpcUa-side tag
+> driver / tag-config editor). See [Historian.md](Historian.md).
 
 Drivers not yet listed above (e.g. Galaxy — which uses the Galaxy address
 picker described below) still use the generic raw-`TagConfig`-JSON textarea.
@@ -226,7 +227,7 @@ Combined with historization (values are arrays — history of the whole array sn
 
 - **Array writes** (inbound client→device write of an array value) — tagged for a follow-up phase.
 - **Multi-dimensional arrays** (`ValueRank > 1`) — not supported; all arrays are 1-D.
-- **Array historization** — a historized array tag materialises with the correct `Historizing` flag, but the Wonderware sidecar historian treats the value as an opaque blob; per-element history is out of scope.
+- **Array historization** — a historized array tag materialises with the correct `Historizing` flag, but the historian backend treats the value as an opaque blob; per-element history is out of scope. (Continuous historization is numeric-analog only — array / non-numeric values are not recorded.)
 
 See the individual driver docs under `docs/drivers/` for per-driver implementation details.