refactor: finish transactional runtime migration

app/db/uow.py

@@ -1,9 +1,65 @@
-"""SQLAlchemy 请求级事务适配器。"""
+"""SQLAlchemy 请求级事务适配器与旧 Oper 事务执行端口。"""
+
+from collections.abc import Awaitable, Callable
+from typing import Protocol, TypeVar
 
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import Session
 
 
+T = TypeVar("T")
+
+
+class SyncTransactionRunner(Protocol):
+    """为无显式 Session 的兼容写入口提供独占同步事务。"""
+
+    def __call__(self, operation: Callable[[Session], T]) -> T:
+        """在一个独占会话中执行并提交操作。"""
+        ...
+
+
+class AsyncTransactionRunner(Protocol):
+    """为无显式 Session 的兼容写入口提供独占异步事务。"""
+
+    def __call__(
+        self,
+        operation: Callable[[AsyncSession], Awaitable[T]],
+    ) -> Awaitable[T]:
+        """在一个独占异步会话中执行并提交操作。"""
+        ...
+
+
+_sync_transaction_runner: SyncTransactionRunner | None = None
+_async_transaction_runner: AsyncTransactionRunner | None = None
+
+
+def configure_transaction_runners(
+    *,
+    sync: SyncTransactionRunner,
+    async_: AsyncTransactionRunner,
+) -> None:
+    """由组合根登记旧 Oper 兼容入口使用的显式事务执行器。"""
+    global _sync_transaction_runner, _async_transaction_runner
+    _sync_transaction_runner = sync
+    _async_transaction_runner = async_
+
+
+def run_sync_transaction(operation: Callable[[Session], T]) -> T:
+    """委托组合根在独占同步事务中执行兼容写操作。"""
+    if _sync_transaction_runner is None:
+        raise RuntimeError("同步事务执行器尚未配置")
+    return _sync_transaction_runner(operation)
+
+
+async def run_async_transaction(
+    operation: Callable[[AsyncSession], Awaitable[T]],
+) -> T:
+    """委托组合根在独占异步事务中执行兼容写操作。"""
+    if _async_transaction_runner is None:
+        raise RuntimeError("异步事务执行器尚未配置")
+    return await _async_transaction_runner(operation)
+
+
 class SqlAlchemyUnitOfWork:
     """把同步 Session 的提交与回滚能力适配为应用层事务端口。"""