M15: synchronize contracts and acceptance

backend/app/api/routers/demo.py

@@ -15,6 +15,7 @@ from app.schemas import CurrentUser, DemoLoginRequest, DemoManifestOut
 from app.seed_loader import reset_and_seed
 from app.services.audit import record_audit_event
 from app.services.demo_manifest import build_demo_manifest, scenario_integrity_report
+from app.services.sessions import revoke_session
 
 router = APIRouter(prefix="/api/v1/demo", tags=["demo"])
 settings = get_settings()
@@ -48,6 +49,7 @@ def demo_login(
             role=user.role,
             display_name=user.display_name,
             issued_at=int(time.time()),
+            session_id=str(uuid.uuid4()),
         )
     )
     response.set_cookie(
@@ -85,7 +87,8 @@ def get_session(
 def demo_logout(request: Request, response: Response, db: Session = Depends(get_db)) -> dict:
     token = request.cookies.get(settings.session_cookie_name)
     payload = read_session_token(token) if token else None
-    if payload is not None:
+    if payload is not None and token is not None:
+        revoke_session(db, token, payload)
         record_audit_event(
             db,
             actor_type="user",