The public-facing facade of Net Lattice.
Re-exports the types consumers need from net-lattice-model and
net-lattice-ip, selects a default backend based on cfg(target_os = "..."), and enforces model convergence: net-lattice-platform's generic
provider traits are constrained here to Net Lattice's own model types,
without net-lattice-platform ever depending on net-lattice-model. See
ARCHITECTURE.md for the full rationale.