Wraps std::shared_ptr<CryptoParametersBase<DCRTPoly>> on the
C++ side. Returned by get_crypto_parameters(cc) and used as
an opaque token for RNS-level parameter accessors such as
get_scaling_factor_real, get_key_switch_technique, etc.
This class ships as scaffolding only: the S7 class definition
is in place so that the getter wiring can treat it as already
defined, but there is no constructor path from R.