Function compact_utc 

pub fn compact_utc(secs: u64) -> String

YYYYMMDDTHHMMSSZ in UTC from a Unix second, the compact form of the layer’s own timestamps.

use majordomus_cli::execution::model::compact_utc;
assert_eq!(compact_utc(0), "19700101T000000Z");
assert_eq!(compact_utc(1_788_000_000), "20260829T104000Z");