- Fix OpenLong/OpenShort: use quantity/ctVal instead of quantity*price/ctVal
- Fix GetPositions: convert contract count to base asset (posAmt = contracts * ctVal)
- Fix CloseLong/CloseShort: convert base asset to contracts before sending order
- Fix GetOrderStatus: convert executedQty from contracts to base asset
- Fix SetStopLoss/SetTakeProfit/FormatQuantity: same contract conversion fix