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

README.md

@@ -31,7 +31,7 @@ Galaxy is the only driver with an external runtime: it speaks gRPC to a separate
 - .NET 10 SDK (server, drivers, clients all target .NET 10)
 - SQL Server reachable for the central config DB
 - For Galaxy specifically: a running `mxaccessgw` deployment — see [docs/v2/Galaxy.ParityRig.md](docs/v2/Galaxy.ParityRig.md)
-- For Wonderware Historian read-back: optional `OtOpcUaWonderwareHistorian` sidecar — see [docs/ServiceHosting.md](docs/ServiceHosting.md)
+- For historian read-back / alarm history / continuous historization: a running [`ZB.MOM.WW.HistorianGateway`](docs/Historian.md) deployment (the sole historian backend; consumed as the `ZB.MOM.WW.HistorianGateway.Client` gRPC package). It must run `RuntimeDb:Enabled=true` + `RuntimeDb:EventReadsEnabled=true`, and the API key must carry `historian:read` + `historian:write` + `historian:tags:write` scopes.
 
 ## Quick Start
 
@@ -48,7 +48,7 @@ The server starts on `opc.tcp://localhost:4840` with the `None` security profile
 
 ## Install as Windows Services
 
-Production deployment is driven by `scripts/install/Install-Services.ps1`, which registers the `OtOpcUa` server service (and optionally the `OtOpcUaWonderwareHistorian` sidecar) under a chosen service account. Galaxy support requires a separately installed `mxaccessgw` — neither this repo nor the install script provisions it.
+Production deployment is driven by `scripts/install/Install-Services.ps1`, which registers the `OtOpcUa` server service under a chosen service account. Historian support requires a separately deployed `ZB.MOM.WW.HistorianGateway` and Galaxy support a separately installed `mxaccessgw` — neither this repo nor the install script provisions them.
 
 ```powershell
 .\scripts\install\Install-Services.ps1 `
@@ -56,7 +56,7 @@ Production deployment is driven by `scripts/install/Install-Services.ps1`, which
     -ServiceAccount 'DOMAIN\svc-otopcua'
 ```
 
-Add `-InstallWonderwareHistorian` for the historian sidecar. See the script header and [docs/ServiceHosting.md](docs/ServiceHosting.md) for full options.
+The historian backend is the external `ZB.MOM.WW.HistorianGateway` (not installed by this script). See the script header and [docs/ServiceHosting.md](docs/ServiceHosting.md) for full options.
 
 ## Client CLI
 
@@ -80,7 +80,7 @@ See [docs/Client.CLI.md](docs/Client.CLI.md) and [docs/Client.UI.md](docs/Client
 | Address space layout | [docs/AddressSpace.md](docs/AddressSpace.md) |
 | Read / Write dispatch (driver vs virtual vs scripted-alarm) | [docs/ReadWriteOperations.md](docs/ReadWriteOperations.md) |
 | Incremental sync (driver-backend rediscovery + config publishes) | [docs/IncrementalSync.md](docs/IncrementalSync.md) |
-| Service hosting (Server + Admin + optional historian sidecar) | [docs/ServiceHosting.md](docs/ServiceHosting.md) |
+| Service hosting (Server + Admin; external HistorianGateway backend) | [docs/ServiceHosting.md](docs/ServiceHosting.md) |
 | Security (transport, LDAP, certificates) | [docs/security.md](docs/security.md) |
 | Redundancy | [docs/Redundancy.md](docs/Redundancy.md) |
 | Status dashboard | [docs/StatusDashboard.md](docs/StatusDashboard.md) |