feat(commons): add cluster/admin/diagnostics client interfaces

src/Core/ZB.MOM.WW.OtOpcUa.Commons/Interfaces/IClusterRoleInfo.cs

@@ -0,0 +1,20 @@
+using ZB.MOM.WW.OtOpcUa.Commons.Types;
+
+namespace ZB.MOM.WW.OtOpcUa.Commons.Interfaces;
+
+/// <summary>
+/// Live view of the local node's identity and the cluster's role topology. Implemented by
+/// <c>ClusterRoleInfo</c> in <c>OtOpcUa.Cluster</c>; consumed by everything that needs to
+/// distinguish admin-role vs driver-role members or react to role-leader changes (e.g. OPC UA
+/// ServiceLevel computation).
+/// </summary>
+public interface IClusterRoleInfo
+{
+    NodeId LocalNode { get; }
+    IReadOnlySet<string> LocalRoles { get; }
+    bool HasRole(string role);
+    IReadOnlyList<NodeId> MembersWithRole(string role);
+    NodeId? RoleLeader(string role);
+
+    event EventHandler<RoleLeaderChangedEventArgs>? RoleLeaderChanged;
+}