chore(config): 添加环境变量示例及.gitignore更新

- 新增 .env.example，包含 Tushare API、钉钉机器人和PostgreSQL数据库配置模板
- 更新.gitignore，忽略本地配置文件如 .env.local 和 config_local.py
- 添加对报表文件命名规则的支持，保留示例文件不忽略
- 删除废弃的 chart.py 及相关图表模块代码
- 新增 config/settings.py，实现从环境变量读取配置的统一接口
- 设置数据目录及缓存目录，确保目录存在，提高配置管理规范性

core/common/utils.py

@@ -0,0 +1,190 @@
+"""
+通用工具函数
+"""
+
+import pandas as pd
+import numpy as np
+from datetime import datetime, timedelta
+from typing import Optional
+
+
+def format_date(date_str: str, output_format: str = "%Y-%m-%d") -> str:
+    """
+    统一日期格式
+
+    Args:
+        date_str: 输入日期字符串（支持 YYYY-MM-DD 或 YYYYMMDD）
+        output_format: 输出格式
+
+    Returns:
+        str: 格式化后的日期字符串
+    """
+    # 尝试解析多种格式
+    for fmt in ["%Y-%m-%d", "%Y%m%d", "%Y/%m/%d"]:
+        try:
+            dt = datetime.strptime(date_str, fmt)
+            return dt.strftime(output_format)
+        except ValueError:
+            continue
+    raise ValueError(f"无法解析日期格式: {date_str}")
+
+
+def get_date_range(
+    start_date: Optional[str] = None,
+    end_date: Optional[str] = None,
+    lookback_days: int = 365,
+) -> tuple[str, str]:
+    """
+    获取日期范围
+
+    Args:
+        start_date: 开始日期，None则根据lookback_days计算
+        end_date: 结束日期，None则使用今天
+        lookback_days: 回溯天数
+
+    Returns:
+        tuple: (start_date, end_date) 格式为 YYYY-MM-DD
+    """
+    if end_date is None:
+        end = datetime.now()
+    else:
+        end = datetime.strptime(format_date(end_date), "%Y-%m-%d")
+
+    if start_date is None:
+        start = end - timedelta(days=lookback_days)
+    else:
+        start = datetime.strptime(format_date(start_date), "%Y-%m-%d")
+
+    return start.strftime("%Y-%m-%d"), end.strftime("%Y-%m-%d")
+
+
+def calculate_cagr(
+    nav_series: pd.Series,
+    method: str = "natural_days",
+) -> float:
+    """
+    计算年化收益率（CAGR）
+
+    Args:
+        nav_series: 净值序列（index=日期）
+        method: 'natural_days' 或 'trading_days'
+
+    Returns:
+        float: CAGR值
+    """
+    total_return = nav_series.iloc[-1] / nav_series.iloc[0]
+
+    if method == "natural_days":
+        days = (nav_series.index[-1] - nav_series.index[0]).days
+        years = days / 365.0
+    elif method == "trading_days":
+        years = len(nav_series) / 252.0
+    else:
+        raise ValueError(f"不支持的CAGR计算方式: {method}")
+
+    if years <= 0:
+        return 0.0
+
+    return total_return ** (1 / years) - 1
+
+
+def calculate_max_drawdown(nav_series: pd.Series) -> tuple[float, datetime, datetime]:
+    """
+    计算最大回撤
+
+    Returns:
+        tuple: (最大回撤比例, 回撤起始日, 回撤结束日)
+    """
+    cummax = nav_series.cummax()
+    drawdown = (nav_series - cummax) / cummax
+
+    max_dd = drawdown.min()
+    end_idx = drawdown.idxmin()
+    start_idx = nav_series[:end_idx].idxmax()
+
+    return max_dd, start_idx, end_idx
+
+
+def calculate_sharpe(
+    returns: pd.Series,
+    rf: float = 0.0,
+    periods: int = 252,
+) -> float:
+    """
+    计算年化夏普比率
+
+    Args:
+        returns: 日收益率序列
+        rf: 无风险利率（年化）
+        periods: 年化系数
+
+    Returns:
+        float: 夏普比率
+    """
+    excess_returns = returns - rf / periods
+    if excess_returns.std() == 0:
+        return 0.0
+    return excess_returns.mean() / excess_returns.std() * np.sqrt(periods)
+
+
+def resample_data(
+    df: pd.DataFrame,
+    timeframe: str,
+    time_col: str = "time",
+) -> pd.DataFrame:
+    """
+    对数据进行重采样
+
+    Args:
+        df: 原始数据
+        timeframe: 目标周期 ('1D', '1W', '1M', '1Y')
+        time_col: 时间列名
+
+    Returns:
+        DataFrame: 重采样后的数据
+    """
+    timeframe_map = {
+        "1D": "D",
+        "1W": "W",
+        "1M": "M",
+        "3M": "3M",
+        "1Y": "Y",
+    }
+
+    if timeframe not in timeframe_map:
+        return df
+
+    df = df.copy()
+    if time_col in df.columns:
+        df[time_col] = pd.to_datetime(df[time_col])
+        df.set_index(time_col, inplace=True)
+
+    rule = timeframe_map[timeframe]
+
+    resampled = (
+        df.resample(rule)
+        .agg(
+            {
+                "open": "first",
+                "high": "max",
+                "low": "min",
+                "close": "last",
+                "volume": "sum",
+            }
+        )
+        .dropna()
+    )
+
+    return resampled.reset_index()
+
+
+def safe_divide(a: float, b: float, default: float = 0.0) -> float:
+    """安全除法，避免除以0"""
+    return a / b if b != 0 else default
+
+
+def truncate_string(s: str, max_length: int = 50, suffix: str = "...") -> str:
+    """截断字符串"""
+    if len(s) <= max_length:
+        return s
+    return s[: max_length - len(suffix)] + suffix