Forwards RubyLLM::Schema to Schematist::Schema. Depend on schematist instead.

A light agent framework on top of RubyLLM. An agent is an object: its fields are state, its methods are what the model can call, and the methods it declares without a body are written by the model at runtime — the method name and prompt are the specification, the schema is the contract. The model acts by writing Ruby that runs on the agent itself.