Function export_graph 

pub fn export_graph(
    nodes: &[Node],
    edges: &[Edge],
    evidence: &[Evidence],
    request: &ExportRequest,
) -> Result<ExportReport, InterfaceError>

Renders a deterministic bounded graph with source-free evidence metadata.

Nodes are ordered by stable key and identifier. Edges are ordered by identifier and are exported only when both endpoints are in the selected node set.

Errors

Returns InterfaceError for invalid bounds, duplicate identities, or JSON serialization failure.