feat(framework): 完成框架入口与集成测试

核心组件：
- ConfigLoader: 配置加载器（YAML支持）
- StrategyConfig: 策略配置数据类
- framework/__init__.py: 框架统一入口

导出接口：
- FactorBase, FactorRegistry, FactorCombiner
- SignalGenerator, TopNSelector, TrendFollower, ReversalTrader
- StrategyBase, RotationStrategy
- RiskControl, StopLossControl, PositionLimitControl
- Executor, BacktestExecutor, DryRunExecutor
- ConfigLoader

集成测试：
- 轮动策略完整流程验证
- 趋势策略完整流程验证
- 回调钩子完整流程验证

总计：62个测试全部通过，框架核心实现完成

framework/__init__.py

@@ -0,0 +1,21 @@
+"""
+量化策略通用框架
+
+融合Freqtrade回调机制 + 模块化因子设计
+"""
+
+from .factors import FactorBase, FactorRegistry, FactorCombiner
+from .signals import SignalGenerator, TopNSelector, TrendFollower, ReversalTrader
+from .strategy import StrategyBase, RotationStrategy
+from .risk import RiskControl, StopLossControl, PositionLimitControl
+from .execution import Executor, BacktestExecutor, DryRunExecutor
+from .config import ConfigLoader
+
+__all__ = [
+    'FactorBase', 'FactorRegistry', 'FactorCombiner',
+    'SignalGenerator', 'TopNSelector', 'TrendFollower', 'ReversalTrader',
+    'StrategyBase', 'RotationStrategy',
+    'RiskControl', 'StopLossControl', 'PositionLimitControl',
+    'Executor', 'BacktestExecutor', 'DryRunExecutor',
+    'ConfigLoader',
+]