feat(worker): implement 6 MXAccess COM commands in executor

Wire up the previously-unimplemented Suspend, Activate, AuthenticateUser,
ArchestrAUserToId, AddBufferedItem, and SetBufferedUpdateInterval command
kinds in MxAccessCommandExecutor. These are real COM calls and run on the
STA via the executor.

- IMxAccessServer gains the 6 methods; MxAccessComServer routes them to the
  right interface version (Suspend/Activate -> ILMXProxyServer4 out MxStatus,
  AuthenticateUser -> base ILMXProxyServer, ArchestrAUserToId ->
  ILMXProxyServer2, AddBufferedItem/SetBufferedUpdateInterval ->
  ILMXProxyServer5).
- Suspend/Activate surface the native MxStatus, converted to MxStatusProxy
  via the existing MxStatusProxyConverter.
- AuthenticateUser hands the credential straight to MXAccess and never logs
  it; native HResult failures propagate via the dispatcher.
- MxAccessSession gains matching pass-throughs; AddBufferedItem registers
  the item handle in the handle registry.
- Unit tests (fake IMxAccessServer / fake COM object) cover each arm plus a
  password-non-leak assertion; existing IMxAccessServer fakes updated.

No proto changes (all request/reply messages already exist).

src/ZB.MOM.WW.MxGateway.Worker/MxAccess/MxAccessSession.cs

@@ -300,6 +300,94 @@ public sealed class MxAccessSession : IDisposable
             MxAccessAdviceKind.Supervisory);
     }
 
+    /// <summary>Suspends data acquisition for an advised item and returns the native MXAccess status.</summary>
+    /// <param name="serverHandle">Handle returned by the worker.</param>
+    /// <param name="itemHandle">Handle returned by the worker.</param>
+    /// <returns>The boxed native MXAccess status produced by the call.</returns>
+    public object Suspend(
+        int serverHandle,
+        int itemHandle)
+    {
+        ThrowIfDisposed();
+
+        return mxAccessServer.Suspend(serverHandle, itemHandle);
+    }
+
+    /// <summary>Reactivates data acquisition for a suspended item and returns the native MXAccess status.</summary>
+    /// <param name="serverHandle">Handle returned by the worker.</param>
+    /// <param name="itemHandle">Handle returned by the worker.</param>
+    /// <returns>The boxed native MXAccess status produced by the call.</returns>
+    public object Activate(
+        int serverHandle,
+        int itemHandle)
+    {
+        ThrowIfDisposed();
+
+        return mxAccessServer.Activate(serverHandle, itemHandle);
+    }
+
+    /// <summary>Authenticates an MXAccess user and returns its user id.</summary>
+    /// <param name="serverHandle">Handle returned by the worker.</param>
+    /// <param name="verifyUser">MXAccess user name to authenticate.</param>
+    /// <param name="verifyUserPassword">Raw MXAccess credential; never logged.</param>
+    /// <returns>The MXAccess user id for the authenticated user.</returns>
+    public int AuthenticateUser(
+        int serverHandle,
+        string verifyUser,
+        string verifyUserPassword)
+    {
+        ThrowIfDisposed();
+
+        return mxAccessServer.AuthenticateUser(serverHandle, verifyUser, verifyUserPassword);
+    }
+
+    /// <summary>Resolves an ArchestrA user GUID to an MXAccess user id.</summary>
+    /// <param name="serverHandle">Handle returned by the worker.</param>
+    /// <param name="userIdGuid">ArchestrA user GUID to resolve.</param>
+    /// <returns>The MXAccess user id for the resolved user.</returns>
+    public int ArchestrAUserToId(
+        int serverHandle,
+        string userIdGuid)
+    {
+        ThrowIfDisposed();
+
+        return mxAccessServer.ArchestrAUserToId(serverHandle, userIdGuid);
+    }
+
+    /// <summary>Adds a buffered item to an MXAccess server and returns the item handle.</summary>
+    /// <param name="serverHandle">Handle returned by the worker.</param>
+    /// <param name="itemDefinition">Definition or address of the item to add.</param>
+    /// <param name="itemContext">Context string for the item.</param>
+    public int AddBufferedItem(
+        int serverHandle,
+        string itemDefinition,
+        string itemContext)
+    {
+        ThrowIfDisposed();
+
+        int itemHandle = mxAccessServer.AddBufferedItem(serverHandle, itemDefinition, itemContext);
+        handleRegistry.RegisterItemHandle(
+            serverHandle,
+            itemHandle,
+            itemDefinition,
+            itemContext,
+            hasItemContext: true);
+
+        return itemHandle;
+    }
+
+    /// <summary>Sets the buffered-update interval for an MXAccess server.</summary>
+    /// <param name="serverHandle">Handle returned by the worker.</param>
+    /// <param name="updateIntervalMilliseconds">Buffered update interval in milliseconds.</param>
+    public void SetBufferedUpdateInterval(
+        int serverHandle,
+        int updateIntervalMilliseconds)
+    {
+        ThrowIfDisposed();
+
+        mxAccessServer.SetBufferedUpdateInterval(serverHandle, updateIntervalMilliseconds);
+    }
+
     /// <summary>Writes a value to an item.</summary>
     /// <param name="serverHandle">Handle returned by the worker.</param>
     /// <param name="itemHandle">Handle returned by the worker.</param>