feat(twincat): BOOL-within-word writes via driver-level parent-word RMW

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT/AdsTwinCATClient.cs

@@ -175,7 +175,9 @@ internal sealed class AdsTwinCATClient : ITwinCATClient
     /// </summary>
     /// <param name="symbolPath">The ADS symbol path to write to.</param>
     /// <param name="type">The TwinCAT data type.</param>
-    /// <param name="bitIndex">Optional bit index for BOOL values (not supported for writes).</param>
+    /// <param name="bitIndex">Optional bit index for BOOL values. BOOL-within-word writes are handled
+    ///     upstream by <see cref="TwinCATDriver.WriteAsync"/> as a parent-word read-modify-write, so a
+    ///     bit index does not reach this method on the write path.</param>
     /// <param name="value">The value to write.</param>
     /// <param name="cancellationToken">The cancellation token.</param>
     /// <returns>The OPC UA status code of the write operation.</returns>
@@ -186,10 +188,6 @@ internal sealed class AdsTwinCATClient : ITwinCATClient
         object? value,
         CancellationToken cancellationToken)
     {
-        if (bitIndex is int && type == TwinCATDataType.Bool)
-            throw new NotSupportedException(
-                "BOOL-within-word writes require read-modify-write; tracked in task #181.");
-
         try
         {
             var converted = ConvertForWrite(type, value);