feat: add versioned backend scoring workflow

backend/wisegrade/db.py

@@ -0,0 +1,22 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import DeclarativeBase, sessionmaker
+
+from .config import get_settings
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+def engine_for(url: str | None = None):
+    url = url or get_settings().database_url
+    return create_engine(url, connect_args={"check_same_thread": False} if url.startswith("sqlite") else {}, pool_pre_ping=True)
+
+
+engine = engine_for()
+SessionLocal = sessionmaker(bind=engine, autoflush=False, expire_on_commit=False)
+
+
+def get_db():
+    with SessionLocal() as session:
+        yield session