feat(twincat): 1-D array symbol read via ADS + IsArray discovery

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Contracts/TwinCATDriverOptions.cs

@@ -70,13 +70,19 @@ public sealed record TwinCATDeviceOptions(
 ///     One TwinCAT-backed OPC UA variable. <paramref name="SymbolPath"/> is the full TwinCAT
 ///     symbolic name (e.g. <c>MAIN.bStart</c>, <c>GVL.Counter</c>, <c>Motor1.Status.Running</c>).
 /// </summary>
+/// <param name="ArrayLength">
+///     When non-null, this tag is a 1-D array of <paramref name="ArrayLength"/> elements of
+///     <paramref name="DataType"/>. Drives <c>IsArray</c>/<c>ArrayDim</c> at discovery and a
+///     native ADS array read at runtime (Phase 4c). <c>null</c> = scalar (the default).
+/// </param>
 public sealed record TwinCATTagDefinition(
     string Name,
     string DeviceHostAddress,
     string SymbolPath,
     TwinCATDataType DataType,
     bool Writable = true,
-    bool WriteIdempotent = false);
+    bool WriteIdempotent = false,
+    int? ArrayLength = null);
 
 /// <summary>Probe options for TwinCAT connection monitoring.</summary>
 public sealed class TwinCATProbeOptions