Package mermaid reads Mermaid flowcharts as flow sketches and writes
flows as Mermaid. Node labels follow conventions ("req: auth/login@2",
"delay: 2s", "extract: token=$.data.token") that resolve against the
collection; what does not resolve becomes a placeholder note, so a
sketch always imports and shows what is left to do.
Export writes f as a flowchart. Supported nodes get convention labels
and import back as themselves; containers become subgraphs (export
only); other nodes are labelled "<type> <id>" and import as
placeholders.