Stateful LangChain Graph Design

Using LangChain and LangGraph, implement a state diagram that accepts property structural metrics (core-to-window distance, plumbing shafts, operable window flags) and routes through a 'zoning_checker' node and a 'cost_estimator' node. Return a structured pydantic model with feasibility_score, estimated_cost_sqft, and egress_compliant.