fix(probe): bound OpcUaClient/AbCip handshakes by timeout CTS; IPv4 preflight; stop sw (code-review)

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriverProbe.cs

@@ -59,12 +59,17 @@ public sealed class AbCipDriverProbe : IDriverProbe
         var host = parsed.Gateway;
         var port = parsed.Port;
 
+        // Bound both phases by the caller timeout, independent of `ct`, so a device that accepts
+        // TCP but stalls the CIP Forward Open cannot hang the probe.
+        using var cts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+        cts.CancelAfter(timeout);
+
         // Phase 1: bare TCP preflight — fast rejection for unreachable hosts.
         var sw = Stopwatch.StartNew();
         try
         {
             using var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
-            await socket.ConnectAsync(host, port, ct);
+            await socket.ConnectAsync(host, port, cts.Token);
         }
         catch (SocketException ex)
         {
@@ -106,7 +111,7 @@ public sealed class AbCipDriverProbe : IDriverProbe
         var rt = new LibplctagTagRuntime(p);
         try
         {
-            await rt.InitializeAsync(ct);
+            await rt.InitializeAsync(cts.Token);
             sw.Stop();
 
             // InitializeAsync completed without throwing — either the tag was found (Ok) or
@@ -131,7 +136,10 @@ public sealed class AbCipDriverProbe : IDriverProbe
         {
             // LibPlcTagException carries the Status; classify as reachable vs transport failure.
             if (IsReachableException(ex))
+            {
+                sw.Stop();
                 return new(true, "CIP session OK (controller reachable; probe tag not found)", sw.Elapsed);
+            }
 
             return new(false, $"Reachable at {host}:{port} but CIP handshake failed: {ex.Message}", null);
         }