Function activate_on_corpus_human 

pub fn activate_on_corpus_human(
    service: &str,
    form: Form<ActivateOnCorpusForm>,
    session: Option<AdminSession>,
    pool: &State<DbPool>,
    database_url: &State<DatabaseUrl>,
) -> Result<Redirect, Status>

Activates an existing service on the chosen corpus — a background service_activate job (the operator tracks it on /jobs). Gated by the signed-in AdminSession cookie (anonymous → sign-in). Redirects to /jobs. 404 on an unknown service/corpus. (The agent twin is POST /api/corpora/<c>/services/<s>.)