Auto: ablegacy-7 — array contiguous block addressing

Closes #250

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/IAbLegacyTagRuntime.cs

@@ -13,6 +13,16 @@ public interface IAbLegacyTagRuntime : IDisposable
     int GetStatus();
     object? DecodeValue(AbLegacyDataType type, int? bitIndex);
     void EncodeValue(AbLegacyDataType type, int? bitIndex, object? value);
+
+    /// <summary>
+    ///     PR 7 — decode element <paramref name="elementIndex"/> of an N-element contiguous
+    ///     block read. Implementations call the same per-element accessors used by
+    ///     <see cref="DecodeValue"/> at offset <c>elementIndex × elementBytes</c>. Default
+    ///     implementation throws so existing fakes that don't override remain explicit.
+    /// </summary>
+    object? DecodeArrayElement(AbLegacyDataType type, int elementIndex)
+        => throw new NotSupportedException(
+            "Array decoding requires an IAbLegacyTagRuntime that overrides DecodeArrayElement.");
 }
 
 public interface IAbLegacyTagFactory
@@ -26,4 +36,5 @@ public sealed record AbLegacyTagCreateParams(
     string CipPath,
     string LibplctagPlcAttribute,
     string TagName,
-    TimeSpan Timeout);
+    TimeSpan Timeout,
+    int ElementCount = 1);