fix: 代码审查问题修复

- unit_of_work.py: 简化为纯 session 上下文管理器,消除 double-close 风险
- validation.py: 移除未使用的 import,简化 _score_to_1x2 逻辑
- repositories.py: 将 func 导入移到模块顶层
- 更新所有 get_uow() 调用点使用新接口(yield session 而非 uow 对象)

src/db/unit_of_work.py

@@ -1,63 +1,33 @@
 """工作单元(Unit of Work):统一事务边界。
 
 使用方式:
-    async with UnitOfWork(db) as uow:
-        await uow.matches.get_by_id(1)
-        await uow.matches.add(new_match)
-        # 退出时自动 commit,异常时 rollback
+    async with get_uow() as uow:
+        await uow.session.get(Match, 1)
+        await uow.commit()
 """
 from __future__ import annotations
 
 from collections.abc import AsyncIterator
 from contextlib import asynccontextmanager
-from typing import AsyncGenerator
-
-from sqlalchemy.ext.asyncio import AsyncSession
 
 from src.db.base import AsyncSessionLocal
 
 
-class UnitOfWork:
-    """工作单元:封装事务边界。"""
-
-    def __init__(self, session: AsyncSession) -> None:
-        self._session = session
-        self.committed = False
-
-    @property
-    def session(self) -> AsyncSession:
-        return self._session
-
-    async def commit(self) -> None:
-        await self._session.commit()
-        self.committed = True
-
-    async def rollback(self) -> None:
-        await self._session.rollback()
-
-    async def close(self) -> None:
-        await self._session.close()
-
-    async def __aenter__(self) -> "UnitOfWork":
-        return self
-
-    async def __aexit__(self, exc_type, exc_val, exc_tb) -> None:
-        if exc_type is not None:
-            await self.rollback()
-        await self.close()
-
-
 @asynccontextmanager
-async def get_uow() -> AsyncGenerator[UnitOfWork, None]:
-    """创建新的工作单元(用于非路由上下文)。"""
+async def get_uow() -> AsyncIterator[AsyncSessionLocal]:
+    """创建新的工作单元(用于非路由上下文)。
+
+    用法:
+        async with get_uow() as session:
+            await session.get(...)
+            # 退出时自动 commit(无异常) 或 rollback(有异常)
+    """
     session = AsyncSessionLocal()
-    uow = UnitOfWork(session)
     try:
-        yield uow
-        if not uow.committed:
-            await uow.commit()
+        yield session
+        await session.commit()
     except Exception:
-        await uow.rollback()
+        await session.rollback()
         raise
     finally:
-        await uow.close()
+        await session.close()