feat(factor): wire up builtin factor auto-registration and export

src/easy_tdx/factor/__init__.py

@@ -1,7 +1,18 @@
 # src/easy_tdx/factor/__init__.py
 """因子研究模块。"""
+from __future__ import annotations
 
 from easy_tdx.factor.base import FACTORY_REGISTRY, Factor, register_factor
 from easy_tdx.factor.engine import FactorEngine
 
-__all__ = ["Factor", "register_factor", "FACTORY_REGISTRY", "FactorEngine"]
+# 导入 builtin 触发自动注册
+from easy_tdx.factor.builtin import get_factor, list_factors  # noqa: F401
+
+__all__ = [
+    "Factor",
+    "register_factor",
+    "FACTORY_REGISTRY",
+    "FactorEngine",
+    "list_factors",
+    "get_factor",
+]

src/easy_tdx/factor/builtin/__init__.py

@@ -1,2 +1,41 @@
-"""内置因子包 — 导入即注册。"""
+"""内置因子库 — 导入子模块触发注册。"""
 from __future__ import annotations
+
+from easy_tdx.factor.base import FACTORY_REGISTRY, Factor
+
+# 导入所有子模块以触发 @register_factor 装饰器
+from easy_tdx.factor.builtin import (  # noqa: F401
+    chanlun,
+    momentum,
+    quality,
+    technical,
+    value,
+    volatility,
+    volume,
+)
+
+
+def list_factors() -> list[dict[str, str | tuple[str, ...]]]:
+    """返回所有已注册因子的元数据。"""
+    return [
+        {
+            "name": cls.name,
+            "category": cls.category,
+            "description": cls.description,
+            "inputs": cls.inputs,
+        }
+        for cls in FACTORY_REGISTRY.values()
+    ]
+
+
+def get_factor(name: str) -> type[Factor]:
+    """按名称获取因子类。
+
+    Raises:
+        ValueError: 因子不存在。
+    """
+    if name not in FACTORY_REGISTRY:
+        raise ValueError(
+            f"未知因子: {name!r}。可用因子: {sorted(FACTORY_REGISTRY.keys())}"
+        )
+    return FACTORY_REGISTRY[name]