Emergency stops: if a swap stalls on Avalanche, cancel pending tx, raise gas slightly, re-quote

https://source-wiki.win/index.php/How_to_Trade_on_Avalanche:_Low_Slippage,_Low_Fees,_Fast_Settlements

Emergency stops: if a swap stalls on Avalanche, cancel pending tx, raise gas slightly, re-quote, and retry with tighter parameters for success.