fix(trader): separate stop-loss and take-profit order cancellation to prevent accidental deletions

## Problem
When adjusting stop-loss or take-profit levels, `CancelStopOrders()` deleted BOTH stop-loss AND take-profit orders simultaneously, causing:
- **Adjusting stop-loss** → Take-profit order deleted → Position has no exit plan ❌
- **Adjusting take-profit** → Stop-loss order deleted → Position unprotected ❌

**Root cause:**
```go
CancelStopOrders(symbol) {
  // Cancelled ALL orders with type STOP_MARKET or TAKE_PROFIT_MARKET
  // No distinction between stop-loss and take-profit
}
```

## Solution

### 1. Added new interface methods (trader/interface.go)
```go
CancelStopLossOrders(symbol string) error      // Only cancel stop-loss orders
CancelTakeProfitOrders(symbol string) error    // Only cancel take-profit orders
CancelStopOrders(symbol string) error          // Deprecated (cancels both)
```

### 2. Implemented for all 3 exchanges

**Binance (trader/binance_futures.go)**:
- `CancelStopLossOrders`: Filters `OrderTypeStopMarket | OrderTypeStop`
- `CancelTakeProfitOrders`: Filters `OrderTypeTakeProfitMarket | OrderTypeTakeProfit`
- Full order type differentiation ✅

**Hyperliquid (trader/hyperliquid_trader.go)**:
- ⚠️ Limitation: SDK's OpenOrder struct doesn't expose trigger field
- Both methods call `CancelStopOrders` (cancels all pending orders)
- Trade-off: Safe but less precise

**Aster (trader/aster_trader.go)**:
- `CancelStopLossOrders`: Filters `STOP_MARKET | STOP`
- `CancelTakeProfitOrders`: Filters `TAKE_PROFIT_MARKET | TAKE_PROFIT`
- Full order type differentiation ✅

### 3. Usage in auto_trader.go
When `update_stop_loss` or `update_take_profit` actions are implemented, they will use:
```go
// update_stop_loss:
at.trader.CancelStopLossOrders(symbol)  // Only cancel SL, keep TP
at.trader.SetStopLoss(...)

// update_take_profit:
at.trader.CancelTakeProfitOrders(symbol)  // Only cancel TP, keep SL
at.trader.SetTakeProfit(...)
```

## Impact
- ✅ Adjusting stop-loss no longer deletes take-profit
- ✅ Adjusting take-profit no longer deletes stop-loss
- ✅ Backward compatible: `CancelStopOrders` still exists (deprecated)
- ⚠️ Hyperliquid limitation: still cancels all orders (SDK constraint)

## Testing
- ✅ Compiles successfully across all 3 exchanges
- ⚠️ Requires live testing:
  - [ ] Binance: Adjust SL → verify TP remains
  - [ ] Binance: Adjust TP → verify SL remains
  - [ ] Hyperliquid: Verify behavior with limitation
  - [ ] Aster: Verify order filtering works correctly

## Code Changes
```
trader/interface.go: +9 lines (new interface methods)
trader/binance_futures.go: +133 lines (3 new functions)
trader/hyperliquid_trader.go: +56 lines (3 new functions)
trader/aster_trader.go: +157 lines (3 new functions)
Total: +355 lines
```

trader/binance_futures.go

@@ -411,6 +411,137 @@ func (t *FuturesTrader) CloseShort(symbol string, quantity float64) (map[string]
 	return result, nil
 }
 
+// CancelStopOrders 取消该币种的止盈/止损单（已废弃：会同时删除止损和止盈）
+func (t *FuturesTrader) CancelStopOrders(symbol string) error {
+	// 获取该币种的所有未完成订单
+	orders, err := t.client.NewListOpenOrdersService().
+		Symbol(symbol).
+		Do(context.Background())
+
+	if err != nil {
+		return fmt.Errorf("获取未完成订单失败: %w", err)
+	}
+
+	// 过滤出止盈止损单并取消
+	canceledCount := 0
+	for _, order := range orders {
+		orderType := order.Type
+
+		// 只取消止损和止盈订单
+		if orderType == futures.OrderTypeStopMarket ||
+			orderType == futures.OrderTypeTakeProfitMarket ||
+			orderType == futures.OrderTypeStop ||
+			orderType == futures.OrderTypeTakeProfit {
+
+			_, err := t.client.NewCancelOrderService().
+				Symbol(symbol).
+				OrderID(order.OrderID).
+				Do(context.Background())
+
+			if err != nil {
+				log.Printf("  ⚠ 取消订单 %d 失败: %v", order.OrderID, err)
+				continue
+			}
+
+			canceledCount++
+			log.Printf("  ✓ 已取消 %s 的止盈/止损单 (订单ID: %d, 类型: %s)",
+				symbol, order.OrderID, orderType)
+		}
+	}
+
+	if canceledCount == 0 {
+		log.Printf("  ℹ %s 没有止盈/止损单需要取消", symbol)
+	} else {
+		log.Printf("  ✓ 已取消 %s 的 %d 个止盈/止损单", symbol, canceledCount)
+	}
+
+	return nil
+}
+
+// CancelStopLossOrders 仅取消止损单（不影响止盈单）
+func (t *FuturesTrader) CancelStopLossOrders(symbol string) error {
+	// 获取该币种的所有未完成订单
+	orders, err := t.client.NewListOpenOrdersService().
+		Symbol(symbol).
+		Do(context.Background())
+
+	if err != nil {
+		return fmt.Errorf("获取未完成订单失败: %w", err)
+	}
+
+	// 过滤出止损单并取消
+	canceledCount := 0
+	for _, order := range orders {
+		orderType := order.Type
+
+		// 只取消止损订单（不取消止盈订单）
+		if orderType == futures.OrderTypeStopMarket || orderType == futures.OrderTypeStop {
+			_, err := t.client.NewCancelOrderService().
+				Symbol(symbol).
+				OrderID(order.OrderID).
+				Do(context.Background())
+
+			if err != nil {
+				log.Printf("  ⚠ 取消止损单 %d 失败: %v", order.OrderID, err)
+				continue
+			}
+
+			canceledCount++
+			log.Printf("  ✓ 已取消止损单 (订单ID: %d, 类型: %s)", order.OrderID, orderType)
+		}
+	}
+
+	if canceledCount == 0 {
+		log.Printf("  ℹ %s 没有止损单需要取消", symbol)
+	} else {
+		log.Printf("  ✓ 已取消 %s 的 %d 个止损单", symbol, canceledCount)
+	}
+
+	return nil
+}
+
+// CancelTakeProfitOrders 仅取消止盈单（不影响止损单）
+func (t *FuturesTrader) CancelTakeProfitOrders(symbol string) error {
+	// 获取该币种的所有未完成订单
+	orders, err := t.client.NewListOpenOrdersService().
+		Symbol(symbol).
+		Do(context.Background())
+
+	if err != nil {
+		return fmt.Errorf("获取未完成订单失败: %w", err)
+	}
+
+	// 过滤出止盈单并取消
+	canceledCount := 0
+	for _, order := range orders {
+		orderType := order.Type
+
+		// 只取消止盈订单（不取消止损订单）
+		if orderType == futures.OrderTypeTakeProfitMarket || orderType == futures.OrderTypeTakeProfit {
+			_, err := t.client.NewCancelOrderService().
+				Symbol(symbol).
+				OrderID(order.OrderID).
+				Do(context.Background())
+
+			if err != nil {
+				log.Printf("  ⚠ 取消止盈单 %d 失败: %v", order.OrderID, err)
+				continue
+			}
+
+			canceledCount++
+			log.Printf("  ✓ 已取消止盈单 (订单ID: %d, 类型: %s)", order.OrderID, orderType)
+		}
+	}
+
+	if canceledCount == 0 {
+		log.Printf("  ℹ %s 没有止盈单需要取消", symbol)
+	} else {
+		log.Printf("  ✓ 已取消 %s 的 %d 个止盈单", symbol, canceledCount)
+	}
+
+	return nil
+}
+
 // CancelAllOrders 取消该币种的所有挂单
 func (t *FuturesTrader) CancelAllOrders(symbol string) error {
 	err := t.client.NewCancelAllOpenOrdersService().