Auto: abcip-2.3 — descriptions to OPC UA Description

Threads tag/UDT-member descriptions captured by the L5K (#346) and L5X
(#347) parsers through AbCipTagDefinition + AbCipStructureMember into
DriverAttributeInfo, so the address-space builder sets the OPC UA
Description attribute on each Variable node. L5kMember and L5xParser
also now capture per-member descriptions (via the (Description := "...")
attribute block on L5K and the <Description> child on L5X), and
L5kIngest forwards them. DriverNodeManager surfaces
DriverAttributeInfo.Description as the Variable's Description property.

Description is added as a trailing optional parameter on
DriverAttributeInfo (default null) so every other driver continues
to construct the record unchanged.

Closes #231

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/Import/L5kIngest.cs

@@ -55,7 +55,11 @@ public sealed class L5kIngest
                 var atomic = TryMapAtomic(m.DataType);
                 var memberType = atomic ?? AbCipDataType.Structure;
                 var writable = !IsReadOnly(m.ExternalAccess) && !IsAccessNone(m.ExternalAccess);
-                members.Add(new AbCipStructureMember(m.Name, memberType, writable));
+                members.Add(new AbCipStructureMember(
+                    Name: m.Name,
+                    DataType: memberType,
+                    Writable: writable,
+                    Description: m.Description));
             }
             udtIndex[dt.Name] = members;
         }
@@ -101,7 +105,8 @@ public sealed class L5kIngest
                 TagPath: tagPath,
                 DataType: dataType,
                 Writable: writable,
-                Members: members));
+                Members: members,
+                Description: t.Description));
         }
 
         return new L5kIngestResult(tags, skippedAliases, skippedNoAccess);