Function stamp_of 

pub fn stamp_of(seconds: i64) -> String

The RFC 3339 stamp of seconds since the epoch — the inverse of epoch_seconds.

use majordomus_cli::reasoning::{epoch_seconds, stamp_of};

let s = "2026-10-01T09:30:00Z";
assert_eq!(stamp_of(epoch_seconds(s).unwrap()), s);