fix(trader): harden API calls with timeouts, strict balance parsing, error context

- binance/bybit/gate: SDK default http.DefaultClient has no timeout; use a
  dedicated 30s-timeout client so a hung connection cannot stall the loop
- bybit: stop mutating http.DefaultClient.Transport, which leaked the
  referer header into every other HTTP request in the process
- add types.ParseFloatField: empty exchange fields stay zero, but malformed
  numeric values now surface as errors instead of silently becoming zero
  balances (applied to GetBalance across 8 exchanges)
- wrap order/market-data errors in auto_trader_orders and okx cancel paths
  with symbol context; log per-order cancel failures in okx CancelAllOrders

trader/okx/trader_account.go

@@ -55,13 +55,20 @@ func (t *OKXTrader) GetBalance() (map[string]interface{}, error) {
 	var usdtAvail, usdtUPL float64
 	for _, detail := range balance.Details {
 		if detail.Ccy == "USDT" {
-			usdtAvail, _ = strconv.ParseFloat(detail.AvailBal, 64)
-			usdtUPL, _ = strconv.ParseFloat(detail.UPL, 64)
+			if usdtAvail, err = types.ParseFloatField("availBal", detail.AvailBal); err != nil {
+				return nil, err
+			}
+			if usdtUPL, err = types.ParseFloatField("upl", detail.UPL); err != nil {
+				return nil, err
+			}
 			break
 		}
 	}
 
-	totalEq, _ := strconv.ParseFloat(balance.TotalEq, 64)
+	totalEq, err := types.ParseFloatField("totalEq", balance.TotalEq)
+	if err != nil {
+		return nil, err
+	}
 
 	result := map[string]interface{}{
 		"totalWalletBalance":    totalEq,

trader/okx/trader_orders.go

@@ -508,7 +508,7 @@ func (t *OKXTrader) cancelAlgoOrders(symbol string, orderType string) error {
 	path := fmt.Sprintf("%s?instType=SWAP&instId=%s&ordType=conditional", okxAlgoPendingPath, instId)
 	data, err := t.doRequest("GET", path, nil)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to get pending algo orders for %s: %w", symbol, err)
 	}
 
 	var orders []struct {
@@ -517,7 +517,7 @@ func (t *OKXTrader) cancelAlgoOrders(symbol string, orderType string) error {
 	}
 
 	if err := json.Unmarshal(data, &orders); err != nil {
-		return err
+		return fmt.Errorf("failed to parse pending algo orders for %s: %w", symbol, err)
 	}
 
 	canceledCount := 0
@@ -552,7 +552,7 @@ func (t *OKXTrader) CancelAllOrders(symbol string) error {
 	path := fmt.Sprintf("%s?instType=SWAP&instId=%s", okxPendingOrdersPath, instId)
 	data, err := t.doRequest("GET", path, nil)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to get pending orders for %s: %w", symbol, err)
 	}
 
 	var orders []struct {
@@ -561,7 +561,7 @@ func (t *OKXTrader) CancelAllOrders(symbol string) error {
 	}
 
 	if err := json.Unmarshal(data, &orders); err != nil {
-		return err
+		return fmt.Errorf("failed to parse pending orders for %s: %w", symbol, err)
 	}
 
 	// Batch cancel
@@ -570,11 +570,15 @@ func (t *OKXTrader) CancelAllOrders(symbol string) error {
 			"instId": order.InstId,
 			"ordId":  order.OrdId,
 		}
-		t.doRequest("POST", okxCancelOrderPath, body)
+		if _, err := t.doRequest("POST", okxCancelOrderPath, body); err != nil {
+			logger.Infof("  ⚠ Failed to cancel order %s for %s: %v", order.OrdId, symbol, err)
+		}
 	}
 
 	// Also cancel algo orders
-	t.cancelAlgoOrders(symbol, "")
+	if err := t.cancelAlgoOrders(symbol, ""); err != nil {
+		logger.Infof("  ⚠ Failed to cancel algo orders for %s: %v", symbol, err)
+	}
 
 	if len(orders) > 0 {
 		logger.Infof("  ✓ Canceled all pending orders for %s", symbol)