fix: use taker fees (BG 0.06%, HL 0.045%) + threshold 0.25%

All IOC market orders incur taker fees, not maker fees. Previous
makerFees (BG 0.02%, HL 0.015%) caused 0.10% threshold trades to
actually lose 0.11% per round trip.

Changes:
- scanner.go: makerFees → takerFees (BG 0.060, HL 0.045)
- dashboard.go: makerFees → takerFees
- types.go: makerFees → takerFees
- trader.go: makerFees → takerFees
- config.json: trade_threshold 0.1 → 0.25

dashboard.go

@@ -379,7 +379,7 @@ func (d *Dashboard) broadcastLoop() {
 					shortAvg := weightedAvgPrice(pos.ShortEntryPrices, pos.AmountUSD/float64(max(1, len(pos.ShortEntryPrices))))
 					longPnl := (longCurrent - longAvg) / longAvg * 100
 					shortPnl := (shortAvg - shortCurrent) / shortAvg * 100
-					totalFees := 2 * (makerFees[ExBitget] + makerFees[ExHyperLiquid])
+					totalFees := 2 * (takerFees[ExBitget] + takerFees[ExHyperLiquid])
 					netPnl := longPnl + shortPnl - totalFees
 
 					currentSpread := (hlP - bgP) / bgP * 100