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_loop.go

@@ -350,7 +350,7 @@ func (at *AutoTrader) buildTradingContext() (*kernel.Context, error) {
 
 		// Calculate margin used (estimated)
 		leverage := 10 // Default value, should actually be fetched from position info
-		if lev, ok := pos["leverage"].(float64); ok {
+		if lev := posFloat64(pos, "leverage"); lev > 0 {
 			leverage = int(lev)
 		}
 		marginUsed := (quantity * markPrice) / float64(leverage)
@@ -374,7 +374,7 @@ func (at *AutoTrader) buildTradingContext() (*kernel.Context, error) {
 		}
 		// Priority 2: Get from exchange API (Bybit: createdTime, OKX: createdTime)
 		if updateTime == 0 {
-			if createdTime, ok := pos["createdTime"].(int64); ok && createdTime > 0 {
+			if createdTime := posInt64(pos, "createdTime"); createdTime > 0 {
 				updateTime = createdTime
 			}
 		}