fix(mesh-phase5): dial supervisor — re-dial on endpoint change, pin no-restart invariant, throttle skip warnings

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

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Telemetry/TelemetryNodeSource.cs

@@ -29,6 +29,10 @@ public static class TelemetryNodeSource
         ArgumentNullException.ThrowIfNull(dbFactory);
         ArgumentNullException.ThrowIfNull(logger);
 
+        // A persistently null-GrpcPort node is skipped on every refresh (every ContactRefreshSeconds);
+        // warn once per node id so it does not spam the log forever.
+        var warnedNullPort = new HashSet<string>(StringComparer.Ordinal);
+
         return async () =>
         {
             await using var db = await dbFactory.CreateDbContextAsync().ConfigureAwait(false);
@@ -44,9 +48,14 @@ public static class TelemetryNodeSource
             {
                 if (row.GrpcPort is null)
                 {
-                    logger.LogWarning(
-                        "ClusterNode {NodeId} has no GrpcPort; it exposes no telemetry stream and is "
-                        + "skipped in this dial refresh", row.NodeId);
+                    if (warnedNullPort.Add(row.NodeId))
+                    {
+                        logger.LogWarning(
+                            "ClusterNode {NodeId} has no GrpcPort; it exposes no telemetry stream and is "
+                            + "skipped in this dial refresh (further skips of this node are silent)",
+                            row.NodeId);
+                    }
+
                     continue;
                 }