fix: 重连成功后重置 outstandingPings 计数器，修复频繁重连问题

Sources/Nats/NatsConnection.swift

@@ -356,6 +356,10 @@ class ConnectionHandler: ChannelInboundHandler {
         guard let channel = self.channel else {
             throw NatsError.ClientError.internalError("empty channel")
         }
+        
+        // 重连成功后重置 ping 计数器，避免累积的失败计数导致立即断开
+        self.outstandingPings.store(0, ordering: .relaxed)
+        
         // Schedule the task to send a PING periodically
         let pingInterval = TimeAmount.nanoseconds(Int64(self.pingInterval * 1_000_000_000))
         self.pingTask = channel.eventLoop.scheduleRepeatedTask(