feat: add per-client trace mode flag with dynamic parser logger

src/NATS.Server/NatsClient.cs

@@ -54,6 +54,20 @@ public sealed class NatsClient : IDisposable
     public bool ConnectReceived => _flags.HasFlag(ClientFlags.ConnectReceived);
     public ClientClosedReason CloseReason { get; private set; }
 
+    public void SetTraceMode(bool enabled)
+    {
+        if (enabled)
+        {
+            _flags.SetFlag(ClientFlags.TraceMode);
+            _parser.Logger = _logger;
+        }
+        else
+        {
+            _flags.ClearFlag(ClientFlags.TraceMode);
+            _parser.Logger = _options.Trace ? _logger : null;
+        }
+    }
+
     public DateTime StartTime { get; }
     private long _lastActivityTicks;
     public DateTime LastActivity => new(Interlocked.Read(ref _lastActivityTicks), DateTimeKind.Utc);