Auto: abcip-2.6 — AOI input/output handling

AOI-aware browse paths: AOI instances now fan out under directional
sub-folders (Inputs/, Outputs/, InOut/) instead of a flat layout. The
sub-folders only appear when at least one member carries a non-Local
AoiQualifier, so plain UDT tags keep the pre-2.6 flat structure.

- Add AoiQualifier enum (Local / Input / Output / InOut) + new property
  on AbCipStructureMember (defaults to Local).
- L5K parser learns ADD_ON_INSTRUCTION_DEFINITION blocks; PARAMETER
  entries' Usage attribute flows through L5kMember.Usage.
- L5X parser captures the Usage attribute on <Parameter> elements.
- L5kIngest maps Usage strings (Input/Output/InOut) to AoiQualifier;
  null + unknown values map to Local.
- AbCipDriver.DiscoverAsync groups directional members under
  Inputs / Outputs / InOut sub-folders when any member is non-Local.
- Tests for L5K AOI block parsing, L5X Usage capture, ingest mapping
  (both formats), and AOI-vs-plain UDT discovery fan-out.

Closes #234

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriver.cs

@@ -1025,10 +1025,31 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                 if (tag.DataType == AbCipDataType.Structure && tag.Members is { Count: > 0 })
                 {
                     var udtFolder = deviceFolder.Folder(tag.Name, tag.Name);
+                    // PR abcip-2.6 — AOI-aware fan-out. When any member carries a non-Local
+                    // AoiQualifier the tag is treated as an AOI instance: Input / Output / InOut
+                    // members get grouped under sub-folders (Inputs/, Outputs/, InOut/) so the
+                    // browse tree visually matches Studio 5000's AOI parameter tabs. Plain UDT
+                    // tags (every member Local) retain the pre-2.6 flat layout under the parent
+                    // folder so existing browse paths stay stable.
+                    var hasDirectional = tag.Members.Any(m => m.AoiQualifier != AoiQualifier.Local);
+                    IAddressSpaceBuilder? inputsFolder = null;
+                    IAddressSpaceBuilder? outputsFolder = null;
+                    IAddressSpaceBuilder? inOutFolder = null;
                     foreach (var member in tag.Members)
                     {
+                        var parentFolder = udtFolder;
+                        if (hasDirectional)
+                        {
+                            parentFolder = member.AoiQualifier switch
+                            {
+                                AoiQualifier.Input => inputsFolder ??= udtFolder.Folder("Inputs", "Inputs"),
+                                AoiQualifier.Output => outputsFolder ??= udtFolder.Folder("Outputs", "Outputs"),
+                                AoiQualifier.InOut => inOutFolder ??= udtFolder.Folder("InOut", "InOut"),
+                                _ => udtFolder, // Local stays at the AOI root
+                            };
+                        }
                         var memberFullName = $"{tag.Name}.{member.Name}";
-                        udtFolder.Variable(member.Name, member.Name, new DriverAttributeInfo(
+                        parentFolder.Variable(member.Name, member.Name, new DriverAttributeInfo(
                             FullName: memberFullName,
                             DriverDataType: member.DataType.ToDriverDataType(),
                             IsArray: false,