feat: Implement backtest source management and enhance candle data handling
Changes:
- Introduced a new function `_apply_backtest_source_env_from_request` to manage the environment variables for candle, tick, and order book sources based on incoming requests.
- Added a teardown function `_teardown_backtest_source_env` to ensure that environment variables do not persist between requests, enhancing the stability of the backtesting environment.
- Refactored existing code to utilize the new source management functions, improving code readability and maintainability.
- Added new utility functions in `bt_candle_source.py` for fetching and managing candle data, ensuring consistency with live trading data sources.
Impact:
- These changes improve the flexibility and reliability of the backtesting framework, allowing for better management of data sources and reducing the risk of cross-request contamination.
Changes:
- Introduced the `e_min_chg_pct` parameter to define the minimum price change percentage compared to the previous day's close, enhancing the momentum trading strategy.
- Updated various functions and classes to incorporate this new parameter, ensuring it is utilized in both backtesting and live trading scenarios.
- Improved documentation and comments to clarify the purpose and usage of the new parameter across the codebase.
Impact:
- This addition allows for more precise control over trading conditions, potentially increasing the effectiveness of the momentum strategy while maintaining system integrity and performance.
