Function remote_pin_replace_named 

pub async fn remote_pin_replace_named(
    kubo_url: &str,
    service: &str,
    name: &str,
    cid: &str,
    overwrite: bool,
) -> Result<bool>

Pin cid on the remote service and schedule best-effort replacement of stale pins with this name.

With overwrite the fresh pin is added under an in-flight name so no name-based cleanup can touch it; the background worker renames it to the requested name once every stale pin is gone. Returns whether cleanup was scheduled.