dominicrume/cantor8_kya_rails: step-1-mandate/THE-JOB.md

# JOB: step-1-mandate IN: the organisers' Mandate.daml starter (copy, keep their header credit) DO: extend it: counterparty allow-list; keep cap, expiry, revoke, propose/accept OUT: KyaMandate.daml that builds, tests passing: under-cap OK, over-cap FAILS, wrong counterparty FAILS, after-revoke FAILS