Renders the catalog a client can discover as Markdown.
mix snodo.catalog --server MyApp.Server --output catalog.md
mix snodo.catalog --url http://127.0.0.1:4000/mcpExactly one of --server and --url is required. A local server must expose
runtime/0; --url connects through Snodo.Client to a running Streamable
HTTP server. Both paths use the client's discovery and paginated list calls,
so the document reflects the selected protocol's visible catalog. Output
goes to stdout unless --output PATH is given.