Function module_healthcheck 

async fn module_healthcheck(headers: HeaderMap) -> Response

/v1/{module}/healthcheck, reached by legacy clients via the /{module}/healthcheck rewrite.

Divergence from tide-disco: matches any {module} string, so unregistered module names report healthy instead of 404. Constraining it to the registered set would have to track which modules each serve mode mounts; not worth it for a liveness probe.