feat(abcip): 1-D array read via libplctag + IsArray discovery

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Contracts/AbCipDriverOptions.cs

@@ -135,6 +135,10 @@ public sealed record AbCipDeviceOptions(
 ///     GuardLogix controller; non-safety writes violate the safety-partition isolation and are
 ///     rejected by the PLC anyway. Surfaces the intent explicitly instead of relying on the
 ///     write attempt failing at runtime.</param>
+/// <param name="ElementCount">Phase 4c — number of array elements for a 1-D array tag. Defaults
+///     to 1 (scalar). When greater than 1 the tag discovers as an OPC UA array node
+///     (<c>IsArray</c> + <c>ArrayDim</c>) and reads via libplctag's <c>elem_count</c> into an
+///     element-typed CLR array. Ignored for <see cref="AbCipDataType.Structure"/>.</param>
 public sealed record AbCipTagDefinition(
     string Name,
     string DeviceHostAddress,
@@ -143,7 +147,8 @@ public sealed record AbCipTagDefinition(
     bool Writable = true,
     bool WriteIdempotent = false,
     IReadOnlyList<AbCipStructureMember>? Members = null,
-    bool SafetyTag = false);
+    bool SafetyTag = false,
+    int ElementCount = 1);
 
 /// <summary>
 ///     One declared member of a UDT tag. Name is the member identifier on the PLC (e.g. <c>Speed</c>,
@@ -155,7 +160,8 @@ public sealed record AbCipStructureMember(
     string Name,
     AbCipDataType DataType,
     bool Writable = true,
-    bool WriteIdempotent = false);
+    bool WriteIdempotent = false,
+    int ElementCount = 1);
 
 /// <summary>Which AB PLC family the device is — selects the profile applied to connection params.</summary>
 public enum AbCipPlcFamily