harden domain architecture and add lazy Crossref+Unpaywall PDF enrichment with publications workspace refactor

app/api/routers/admin.py

@@ -20,7 +20,7 @@ from app.auth.deps import get_auth_service
 from app.auth.service import AuthService
 from app.db.models import User
 from app.db.session import get_db_session
-from app.services import users as user_service
+from app.services.domains.users import application as user_service
 
 logger = logging.getLogger(__name__)