improving async fastapi sqlmodel skill

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

@@ -100,9 +100,9 @@ Notes:
 
 ## SQLModel Alignment
 
-- If using SQLModel, keep the same session ownership model: one `async_sessionmaker`, one `AsyncSession` per request/unit-of-work.
-- SQLModel does not replace SQLAlchemy async lifecycle primitives; it complements model declaration and typed data handling.
-- During migration, avoid mixed ad hoc patterns where some handlers create SQLAlchemy sessions directly while others use SQLModel-specific wrappers.
+- Use SQLModel as the default model and statement layer while keeping the same session ownership model: one `async_sessionmaker`, one `AsyncSession` per request/unit-of-work.
+- SQLModel does not replace SQLAlchemy async lifecycle primitives; it provides model declaration, validation, and typing ergonomics on top of them.
+- Do not mix ad hoc session construction with the canonical async dependency.
 
 ---
 
@@ -139,9 +139,3 @@ Notes:
 - Parallel-task tests verify no shared AsyncSession instances.
 - Lifespan tests confirm session factory is initialized and teardown-safe.
 
----
-
-## Migration Notes
-
-- If current code uses global/shared sessions, fix scope first before refactoring query style.
-- If legacy sync patterns are present, keep session boundary rules stable while migrating incrementally.