feat(factor): M7.1 因子定义入库 + /api/factors 读库（目录契约源）

- factor_definition 表（migration b7f2a5e81c33，MySQL 已应用）：name 主键 + 元数据
  （formula/brief/frequency/lookback/direction/requires JSON/version）+ FactorDefinition
  entity（from_registry_def 由代码注册表构造）
- FactorRepository Protocol + SQLAlchemy 实现（幂等 upsert/list/get）
- /api/factors 改读 DB；目录为空自动 seed 注册表（幂等）—— 保留自定义因子登记能力
  （计算仍须代码注册，引用未注册因子照常 FactorError，防伪因子）
- tests/test_factor_catalog.py（repo 幂等/roundtrip/registry seed、API seed+字段齐全）；
  test_api 的 client fixture 补 tmp sqlite session（factors 读库）；全量 pytest 通过

backend/app/api/deps.py

@@ -11,6 +11,7 @@ from fastapi import Depends
 from sqlalchemy.orm import Session
 
 from app.application.services.selection_service import SelectionService
+from app.domain.repositories.factor import FactorRepository
 from app.domain.repositories.jobs import ExperimentRepository, JobRepository
 from app.domain.repositories.market import (
     DailyBarRepository,
@@ -18,6 +19,9 @@ from app.domain.repositories.market import (
     StockRepository,
 )
 from app.domain.repositories.selection import SelectionRepository
+from app.infrastructure.persistence.sqlalchemy.repositories.factor_impl import (
+    SqlAlchemyFactorRepository,
+)
 from app.infrastructure.persistence.sqlalchemy.repositories.market_impl import (
     SqlAlchemyDailyBarRepository,
     SqlAlchemyFinancialRepository,
@@ -70,12 +74,17 @@ def _selection_repo_factory(session: DbSession) -> SelectionRepository:
     return SqlAlchemySelectionRepository(session)
 
 
+def _factor_repo_factory(session: DbSession) -> FactorRepository:
+    return SqlAlchemyFactorRepository(session)
+
+
 StockRepoDep = Annotated[StockRepository, Depends(_stock_repo_factory)]
 DailyRepoDep = Annotated[DailyBarRepository, Depends(_daily_repo_factory)]
 EngineDep = Annotated[QuantEngine, Depends(_engine_factory)]
 ResearchServiceDep = Annotated[ResearchService, Depends(_service_factory)]
 SelectionServiceDep = Annotated[SelectionService, Depends(_selection_service_factory)]
 SelectionRepoDep = Annotated[SelectionRepository, Depends(_selection_repo_factory)]
+FactorRepoDep = Annotated[FactorRepository, Depends(_factor_repo_factory)]
 
 
 def _job_repo_factory(session: DbSession):

backend/app/api/factors.py

@@ -1,26 +1,22 @@
-"""因子目录 API：/api/factors。"""
+"""因子目录 API：/api/factors（M7.1 起读 DB factor_definition）。
+
+目录为空时自动从代码注册表 seed（幂等）；随后可登记自定义因子元数据。
+响应为 FactorDefinition 实体（含 requires 列表等）。
+"""
 
 from __future__ import annotations
 
 from fastapi import APIRouter
 
-from app.quant.factors import list_factors
+from app.api.deps import DbSession, FactorRepoDep
+from app.application.services.factor_catalog import seed_registry_factors
+from app.domain.entities.factor import FactorDefinition
 
 router = APIRouter(prefix="/factors", tags=["factors"])
 
 
-@router.get("", summary="因子目录（含元数据）")
-def list_factor_catalog() -> list[dict]:
-    return [
-        {
-            "name": d.name,
-            "description": d.description,
-            "brief": d.brief,
-            "formula": d.formula,
-            "frequency": d.frequency,
-            "lookback": d.lookback,
-            "direction": d.direction,
-            "requires": list(d.requires),
-        }
-        for d in list_factors()
-    ]
+@router.get("", summary="因子目录（含元数据，来自 factor_definition 表）")
+def list_factor_catalog(factor_repo: FactorRepoDep, session: DbSession) -> list[FactorDefinition]:
+    if not factor_repo.list():
+        seed_registry_factors(factor_repo, session)  # 首次：从代码注册表 seed
+    return factor_repo.list()