fix: consistent safe type helpers in auto_trader, log emergency exit errors

- Replace all raw pos["key"].(type) assertions with posFloat64/posString/posInt64 helpers
  across auto_trader_decision, auto_trader_grid, auto_trader_grid_orders,
  auto_trader_grid_regime, auto_trader_loop, auto_trader_orders, auto_trader_risk
- Add posInt64 helper for int64 extraction (createdTime etc)
- Fix emergencyExit: log CloseLong/CloseShort errors instead of silently dropping
- Fix emergencyExit: log GetPositions error on failure
- Upgrade closeAllPositions log level from Infof to Warnf for close failures
- Zero raw type assertions remaining in auto_trader_* files

trader/auto_trader_decision.go

@@ -142,7 +142,7 @@ func (at *AutoTrader) GetAccountInfo() (map[string]interface{}, error) {
 		totalUnrealizedPnLCalculated += unrealizedPnl
 
 		leverage := 10
-		if lev, ok := pos["leverage"].(float64); ok {
+		if lev := posFloat64(pos, "leverage"); lev > 0 {
 			leverage = int(lev)
 		}
 		marginUsed := (quantity * markPrice) / float64(leverage)
@@ -211,7 +211,7 @@ func (at *AutoTrader) GetPositions() ([]map[string]interface{}, error) {
 		liquidationPrice := posFloat64(pos, "liquidationPrice")
 
 		leverage := 10
-		if lev, ok := pos["leverage"].(float64); ok {
+		if lev := posFloat64(pos, "leverage"); lev > 0 {
 			leverage = int(lev)
 		}