feat(mtconnect): host registration + DriverTypeNames const + guard parity (Task 16)

Register the MTConnect factory + probe with the Host, add the
DriverTypeNames.MTConnect constant, and keep DriverTypeNamesGuardTests green.

- DriverTypeNames: new MTConnect const + appended to All.
- DriverFactoryBootstrap: MTConnectDriverFactoryExtensions.Register in
  Register(...) at the default Tier A (managed HttpClient/XML, in-process;
  Tier C is the only tier arming process-recycle, wrong here), and
  TryAddEnumerable(IDriverProbe -> MTConnectDriverProbe) in
  AddOtOpcUaDriverProbes so the probe reaches admin-only nodes (the
  admin-pinned Test-Connect singleton) without double-registering on a
  fused admin,driver node.
- Host.csproj: ProjectReference to Driver.MTConnect (required to compile
  the Register call).
- Core.Abstractions.Tests.csproj: ProjectReference to Driver.MTConnect so
  the guard's bin scan discovers the factory. This and the constant MUST
  land together -- verified RED (2/4 facts) with the constant alone.
- DriverProbeRegistrationTests: MTConnect added to AdminUiDriverTypeKeys;
  its idempotency fact asserts distinct-probe-count and goes RED without
  this (and RED if TryAddEnumerable is downgraded to AddSingleton).

Reconciles all four "MTConnect" literals onto the one constant: the
factory's DriverTypeName, MTConnectDriver.DriverType, and
MTConnectDriverProbe.DriverType now all alias DriverTypeNames.MTConnect
(no circular reference -- Core.Abstractions is a leaf both driver
projects already reference). This is the repo's TwinCat/Focas anti-drift
convention.

src/Server/ZB.MOM.WW.OtOpcUa.Host/Drivers/DriverFactoryBootstrap.cs

@@ -20,6 +20,7 @@ using GalaxyProbe    = Driver.Galaxy.GalaxyDriverProbe;
 using CalculationProbe = Driver.Calculation.CalculationDriverProbe;
 using SqlProbe       = Driver.Sql.SqlDriverProbe;
 using MqttProbe      = Driver.Mqtt.MqttDriverProbe;
+using MTConnectProbe = Driver.MTConnect.MTConnectDriverProbe;
 
 /// <summary>
 ///     Wires every cross-platform driver assembly's <c>Register(registry, loggerFactory)</c>
@@ -126,6 +127,7 @@ public static class DriverFactoryBootstrap
         services.TryAddEnumerable(ServiceDescriptor.Singleton<IDriverProbe, CalculationProbe>());
         services.TryAddEnumerable(ServiceDescriptor.Singleton<IDriverProbe, SqlProbe>());
         services.TryAddEnumerable(ServiceDescriptor.Singleton<IDriverProbe, MqttProbe>());
+        services.TryAddEnumerable(ServiceDescriptor.Singleton<IDriverProbe, MTConnectProbe>());
 
         return services;
     }
@@ -149,6 +151,13 @@ public static class DriverFactoryBootstrap
         Driver.Galaxy.GalaxyDriverFactoryExtensions.Register(registry, secretResolver, loggerFactory);
         Driver.Modbus.ModbusDriverFactoryExtensions.Register(registry, loggerFactory);
         Driver.Mqtt.MqttDriverFactoryExtensions.Register(registry, loggerFactory);
+        // Tier A (the Register default): fully managed — HttpClient + System.Xml.Linq, no native SDK,
+        // no COM. Tier C is the only tier that arms process-level recycle (MemoryRecycle hard-breach /
+        // ScheduledRecycleScheduler), which would be wrong here: the driver is in-process and killing
+        // it kills every OPC UA session. The long-lived /sample stream does not argue for a slower
+        // tier either — SubscribeAsync returns synchronously after starting the pump on a background
+        // task, so the Tier A 5s Subscribe budget never covers the stream's lifetime.
+        Driver.MTConnect.MTConnectDriverFactoryExtensions.Register(registry, loggerFactory);
         Driver.OpcUaClient.OpcUaClientDriverFactoryExtensions.Register(registry, loggerFactory, secretResolver);
         Driver.S7.S7DriverFactoryExtensions.Register(registry);
         Driver.Sql.SqlDriverFactoryExtensions.Register(registry, loggerFactory);