Standalone openapi yaml schema generation

Is it possible to generate a openapi yaml schema file from the command line? Eg running a npm command? Without the server running.

Rationale:
In development workflow I would like to generate the yaml as it will be used as input for another npm task to generate a openapi client.
During (prod) build I would like to run both to make sure everything is correct.

Second question is whether it is possible to disable the docs endpoint and yaml/json when server is running.

The issue names no files, tests, or entry points. First map how Chanfana currently builds and serves OpenAPI schemas, then define the CLI generation and optional endpoint behavior; done criteria should cover generation without a running server and disabling the docs and schema endpoints.

Written by the indexing model from the issue text.