Function try_claim_phase2 

pub fn try_claim_phase2(
    conn: &Connection,
    cwd: &str,
    now: i64,
    lease_seconds: i64,
) -> Result<Option<(String, i64)>>

Try to claim the global Phase 2 job for cwd. Returns Some((token, lease)) when claimed; None when another oxicode process already owns it.