fix: sl_tp_guard 从 ctp_symbol 导入 ths_to_vnpy_symbol

Co-authored-by: Cursor <cursoragent@cursor.com>

sl_tp_guard.py

@@ -7,7 +7,7 @@ import time
 from typing import Any, Callable, Optional
 
 from contract_specs import get_contract_spec
-from symbols import ths_to_vnpy_symbol
+from ctp_symbol import ths_to_vnpy_symbol
 from vnpy_bridge import (
     ctp_list_active_orders,
     ctp_list_positions,