Create the state environment for a caugi (internal)

Internal function to create the state environment for a caugi. This function is not intended to be used directly by users.

Usage

.cg_state(nodes, edges, ptr, built, simple, class, name_index_map)

nodes: A data.table of nodes with a name column.
edges: A data.table of edges with from, edge, and to columns.
ptr: A pointer to the underlying Rust graph structure (or NULL if not built).
built: Logical; whether the graph has been built.
simple: Logical; whether the graph is simple (no parallel edges or self-loops).
class: Character; one of "UNKNOWN", "DAG", "UG", "PDAG", "ADMG", or "AG".
name_index_map: A fastmap mapping node names to their zero indexed indices.

An environment containing the graph state.