feat(mesh): ClusterRoleInfo exposes the node's own cluster-scoped role

Phase 6 Task 1. IClusterRoleInfo gains ClusterRole/ClusterId, derived from
the node's configured AkkaClusterOptions.Roles at construction time (not
live Cluster.State) so the identity is available before the cluster forms.
First cluster-scoped role wins when more than one is configured, logged as
a Warning. Updates the FakeClusterRoleInfo test double in
ServiceCollectionExtensionsTests to satisfy the new interface members.

Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW

src/Core/ZB.MOM.WW.OtOpcUa.Cluster/ClusterRoleInfo.cs

@@ -20,6 +20,8 @@ public sealed class ClusterRoleInfo : IClusterRoleInfo, IDisposable
     private readonly ILogger<ClusterRoleInfo> _logger;
     private readonly CommonsNodeId _localNode;
     private readonly HashSet<string> _localRoles;
+    private readonly string? _clusterRole;
+    private readonly string? _clusterId;
     private readonly object _lock = new();
     private readonly Dictionary<string, Member?> _roleLeaders = new(StringComparer.Ordinal);
     private readonly Dictionary<string, HashSet<Member>> _membersByRole = new(StringComparer.Ordinal);
@@ -39,6 +41,23 @@ public sealed class ClusterRoleInfo : IClusterRoleInfo, IDisposable
         _localNode = CommonsNodeId.Parse($"{options.Value.PublicHostname}:{options.Value.Port}");
         _localRoles = new HashSet<string>(options.Value.Roles, StringComparer.Ordinal);
 
+        // Derived from the node's OWN configured roles (not live Cluster.State) so this identity is
+        // available at host-build time, before the cluster forms. Iterate the ORIGINAL array — not
+        // _localRoles — because first-wins requires configuration order, which HashSet does not
+        // guarantee.
+        var clusterRoles = options.Value.Roles.Where(RoleParser.IsClusterRole).ToArray();
+        if (clusterRoles.Length > 0)
+        {
+            _clusterRole = clusterRoles[0];
+            _clusterId = RoleParser.ClusterIdFromRole(_clusterRole);
+            if (clusterRoles.Length > 1)
+            {
+                _logger.LogWarning(
+                    "Node configured with {Count} cluster-scoped roles ({Roles}); using the first ({ClusterRole})",
+                    clusterRoles.Length, string.Join(", ", clusterRoles), _clusterRole);
+            }
+        }
+
         SeedFromCurrentState();
         _subscriber = system.ActorOf(Props.Create(() => new SubscriberActor(this)), "clusterroleinfo-subscriber");
     }
@@ -49,6 +68,12 @@ public sealed class ClusterRoleInfo : IClusterRoleInfo, IDisposable
     /// <inheritdoc />
     public IReadOnlySet<string> LocalRoles => _localRoles;
 
+    /// <inheritdoc />
+    public string? ClusterRole => _clusterRole;
+
+    /// <inheritdoc />
+    public string? ClusterId => _clusterId;
+
     /// <inheritdoc />
     public bool HasRole(string role) => _localRoles.Contains(role);