Phase 7 follow-up #246 — Phase7Composer + Program.cs wire-in

Activates the Phase 7 engines in production. Loads Script + VirtualTag +
ScriptedAlarm rows from the bootstrapped generation, wires the engines through
the Phase7EngineComposer kernel (#243), starts the DriverSubscriptionBridge feed
(#244), and late-binds the resulting IReadable sources to OpcUaApplicationHost
before OPC UA server start.

## Phase7Composer (Server.Phase7)

Singleton orchestrator. PrepareAsync loads the three Phase 7 row sets in one
DB scope, builds CachedTagUpstreamSource, calls Phase7EngineComposer.Compose,
constructs DriverSubscriptionBridge with one DriverFeed per registered
ISubscribable driver (path-to-fullRef map built from EquipmentNamespaceContent
via MapPathsToFullRefs), starts the bridge.

DisposeAsync tears down in the right order: bridge first (no more events fired
into the cache), then engines (cascades + timers stop), then any disposable sink.

MapPathsToFullRefs: deterministic path convention is
  /{areaName}/{lineName}/{equipmentName}/{tagName}
matching exactly what EquipmentNodeWalker emits into the OPC UA browse tree, so
script literals against the operator-visible UNS tree work without translation.
Tags missing EquipmentId or pointing at unknown Equipment are skipped silently
(Galaxy SystemPlatform-style tags + dangling references handled).

## OpcUaApplicationHost.SetPhase7Sources

New late-bind setter. Throws InvalidOperationException if called after
StartAsync because OtOpcUaServer + DriverNodeManagers capture the field values
at construction; mutation post-start would silently fail.

## OpcUaServerService

After bootstrap loads the current generation, calls phase7Composer.PrepareAsync
+ applicationHost.SetPhase7Sources before applicationHost.StartAsync. StopAsync
disposes Phase7Composer first so the bridge stops feeding the cache before the
OPC UA server tears down its node managers (avoids in-flight cascades surfacing
as noisy shutdown warnings).

## Program.cs

Registers IAlarmHistorianSink as NullAlarmHistorianSink.Instance (task #247
swaps in the real Galaxy.Host-writer-backed SqliteStoreAndForwardSink), Serilog
root logger, and Phase7Composer singleton.

## Tests — 5 new Phase7ComposerMappingTests = 34 Phase 7 tests total

Maps tag → walker UNS path, skips null EquipmentId, skips unknown Equipment
reference, multiple tags under same equipment map distinctly, empty content
yields empty map. Pure functions; no DI/DB needed.

The real PrepareAsync DB query path can't be exercised without SQL Server in
the test environment — it's exercised by the live E2E smoke (task #240) which
unblocks once #247 lands.

## Phase 7 production wiring chain status
- ✅ #243 composition kernel
- ✅ #245 scripted-alarm IReadable adapter
- ✅ #244 driver bridge
- ✅ #246 this — Program.cs wire-in
- 🟡 #247 — Galaxy.Host SqliteStoreAndForwardSink writer adapter (replaces NullSink)
- 🟡 #240 — live E2E smoke (unblocks once #247 lands)

src/ZB.MOM.WW.OtOpcUa.Server/Program.cs

@@ -8,8 +8,10 @@ using Serilog.Formatting.Compact;
 using ZB.MOM.WW.OtOpcUa.Configuration;
 using ZB.MOM.WW.OtOpcUa.Configuration.LocalCache;
 using ZB.MOM.WW.OtOpcUa.Core.Hosting;
+using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
 using ZB.MOM.WW.OtOpcUa.Server;
 using ZB.MOM.WW.OtOpcUa.Server.OpcUa;
+using ZB.MOM.WW.OtOpcUa.Server.Phase7;
 using ZB.MOM.WW.OtOpcUa.Server.Security;
 
 var builder = Host.CreateApplicationBuilder(args);
@@ -113,5 +115,13 @@ builder.Services.AddDbContext<OtOpcUaConfigDbContext>(opt =>
     opt.UseSqlServer(options.ConfigDbConnectionString));
 builder.Services.AddHostedService<HostStatusPublisher>();
 
+// Phase 7 follow-up #246 — historian sink + engine composer. NullAlarmHistorianSink
+// is the default until the Galaxy.Host SqliteStoreAndForwardSink writer adapter
+// lands (task #248). The composer reads Script/VirtualTag/ScriptedAlarm rows on
+// generation bootstrap, builds the engines, and starts the driver-bridge feed.
+builder.Services.AddSingleton<IAlarmHistorianSink>(NullAlarmHistorianSink.Instance);
+builder.Services.AddSingleton(Log.Logger);  // Serilog root for ScriptLoggerFactory
+builder.Services.AddSingleton<Phase7Composer>();
+
 var host = builder.Build();
 await host.RunAsync();