fix: ensure array column order matches codes parameter

The numpy arrays extracted from target_pos and close_df must be
reindexed by the codes parameter to ensure _code_to_col mapping
is consistent regardless of DataFrame internal column order.

Fixes test_rotation_is_independent_of_close_open_symbol_order

Signed-off-by: shadowinlife <shadowinlife@gmail.com>

AI-Contributed/Feature: 0/6
AI-Contributed/UT: 0/0

agent/backtest/engines/base.py

@@ -611,8 +611,10 @@ class BaseEngine(ABC):
     ) -> None:
         """Bar-by-bar execution with market rule enforcement."""
         # Pre-extract numpy arrays for O(1) indexed access instead of DataFrame.at[]
-        _target_arr = target_pos.values  # (n_dates, n_codes) ndarray
-        _close_arr = close_df.values  # (n_dates, n_codes) ndarray
+        # Explicit column reindex ensures array column order matches codes parameter,
+        # regardless of DataFrame internal column ordering (which may be alphabetical).
+        _target_arr = target_pos[codes].values  # (n_dates, n_codes) ndarray
+        _close_arr = close_df[codes].values  # (n_dates, n_codes) ndarray
         _code_to_col = {c: j for j, c in enumerate(codes)}
         # Store as instance attrs for use in _calc_equity / _safe_price
         self._close_arr = _close_arr