feat: add SQLite persistence models

app/db/session.py

@@ -0,0 +1,18 @@
+from sqlalchemy import create_engine
+from sqlalchemy.engine import Engine
+from sqlalchemy.orm import Session, sessionmaker
+
+from app.db.models import Base
+
+
+def create_db_engine(database_url: str) -> Engine:
+    connect_args = {"check_same_thread": False} if database_url.startswith("sqlite") else {}
+    return create_engine(database_url, connect_args=connect_args, future=True)
+
+
+def create_session_factory(engine: Engine) -> sessionmaker[Session]:
+    return sessionmaker(bind=engine, autoflush=False, expire_on_commit=False)
+
+
+def initialize_schema(engine: Engine) -> None:
+    Base.metadata.create_all(engine)