RL Trust Boundary (Umbrella)

Stable import for TorchLean's RL trust-boundary layer. The implementation is split into:

• NN.Runtime.RL.Boundary.Core: contracts, executable checkers, and Prop-level validity predicates;
• NN.Runtime.RL.Boundary.Json: a small JSON rollout schema plus parser/validator for external producers such as Gymnasium scripts.

Use this umbrella when you want the full runtime surface. Proof modules that do not parse JSON can import Boundary.Core directly.