refactor(ptrade): 优化复权计算逻辑并改进除权事件处理

- 移除前复权计算中的多余np.round调用，保持数值精度
- 在后复权处理中移除不必要的四舍五入操作
- 优化除权事件检查逻辑，直接使用整数日期索引进行匹配
- 避免重复的DataFrame列查找和条件判断，提升性能

Author: kay-ou

src/simtradelab/ptrade/api.py

@@ -178,8 +178,8 @@ def _apply_adj_factors(self, stock_df: pd.DataFrame, stock: str, fq: str) -> pd.
                 continue
             if fq == 'pre':
                 # 前复权: (未复权价 - adj_b) / adj_a
-                adjusted_df.loc[common_idx, col] = np.round(
-                    (adjusted_df.loc[common_idx, col] - adj_b) / adj_a, 2
+                adjusted_df.loc[common_idx, col] = (
+                    (adjusted_df.loc[common_idx, col] - adj_b) / adj_a
                 )
             else:
                 # 后复权: adj_a * 未复权价 + adj_b
@@ -750,7 +750,7 @@ def get_history(self, count: int, frequency: str = '1d', field: str | list[str]
                         if needs_adj_dypre:
                             stock_result[field_name] = np.round(pre_price * adj_a_base + adj_b_base, 2)
                         else:
-                            stock_result[field_name] = np.round(pre_price, 2)
+                            stock_result[field_name] = pre_price
                     else:
                         stock_result[field_name] = aligned_df[field_name].values
             # 后复权处理: 后复权价 = adj_a * 未复权价 + adj_b

src/simtradelab/ptrade/strategy_engine.py

@@ -472,17 +472,16 @@ def _process_dividend_events(self, current_date):
                 # 检查除权事件（送股/配股）
                 exrights_df = self.api.data_context.exrights_dict.get(stock_code)
                 if exrights_df is not None and not exrights_df.empty:
-                    if 'date' in exrights_df.columns:
-                        match = exrights_df[exrights_df['date'] == current_date]
-                        if not match.empty:
-                            event = match.iloc[0]
-                            allotted = float(event.get('allotted_ps', 0) or 0)
-                            if allotted > 0:
-                                new_amount = int(original_amount * (1 + allotted))
-                                position.amount = new_amount
-                                position.enable_amount = new_amount
-                                position.cost_basis /= (1 + allotted)
-                                self.context.portfolio._invalidate_cache()
+                    date_int = int(date_str)
+                    if date_int in exrights_df.index:
+                        event = exrights_df.loc[date_int]
+                        allotted = float(event.get('allotted_ps', 0) or 0)
+                        if allotted > 0:
+                            new_amount = int(original_amount * (1 + allotted))
+                            position.amount = new_amount
+                            position.enable_amount = new_amount
+                            position.cost_basis /= (1 + allotted)
+                            self.context.portfolio._invalidate_cache()
 
                 # 现金分红（按登记日股数计算）
                 if stock_code not in self.api.data_context.dividend_cache: