Extends the deadline of the in-flight NebulaAPI call this process is serving.

Call it from inside a defapi body that legitimately runs long: it resets the caller's timeout window (a heartbeat, like a long task pinging its scheduler), so a slow-but-alive body is not mistaken for a hung one and killed.

Outside a remote call — the same body invoked locally, or any other process — it is a no-op: the local path has no caller deadline to extend.