Privacy CLI reference

Subcommand	Purpose
confium privacy psi	Intersect two sets (--set-a, --set-b, --cardinality-only)
confium privacy dp	Apply Laplace/Gaussian noise (--value, --sensitivity, --epsilon)
confium privacy mpc	MPC orchestration (placeholder)

Product docs: https://www.confium.org/privacy/. API reference: docs.rs/confium-privacy.