engine/session updates

docs/skills/async-fastapi-sqlmodel/references/sqlmodel.md

@@ -72,18 +72,15 @@ class UserRead(UserBase):
 ### Pattern B: Keep SQLModel models with the async runtime
 
 ```python
-from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
 from sqlmodel import select
-from sqlmodel.ext.asyncio.session import AsyncSession
 
-engine = create_async_engine(settings.database_url, pool_pre_ping=True)
-session_factory = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
-
-async with session_factory() as session:
-    users = (await session.scalars(select(User))).all()
+async with engine_scope(settings.database_url) as engine:
+    session_factory = create_session_factory(engine)
+    async with session_factory() as session:
+        users = (await session.scalars(select(User))).all()
 ```
 
-`sqlmodel.select()` keeps SQLModel's typing-oriented statement construction, and SQLModel's `AsyncSession` adds typed `exec()` results while retaining SQLAlchemy's async lifecycle and transaction behavior. Import `AsyncSession` from `sqlmodel.ext.asyncio.session` when working with SQLModel models; use SQLAlchemy's `AsyncSession` only when the code intentionally has no SQLModel dependency.
+`engine_scope()` and `create_session_factory()` preserve the canonical lifecycle while SQLModel supplies the model and statement layer. `sqlmodel.select()` keeps SQLModel's typing-oriented statement construction, and SQLModel's `AsyncSession` adds typed `exec()` results while retaining SQLAlchemy's async lifecycle and transaction behavior. Import `AsyncSession` from `sqlmodel.ext.asyncio.session` when working with SQLModel models; use SQLAlchemy's `AsyncSession` only when the code intentionally has no SQLModel dependency.
 
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