Function to_node 

pub fn to_node<T: Serialize>(
    typed: &T,
    schema: &Value,
) -> Result<Node, CodecError>

A typed instance’s codec node (the dictionary contract). The bridge is native serde: the instance serializes to its normalized-JSON wire form (envelope-as-data + Ref<T> values), and the wire form maps onto the node contract through the SAME split deserialize defines — one contract, not two.