New Zealand's Algorithm Charter is short, principle-based, and signatory-voluntary — and it operationalises into a production-grade AI governance architecture that is portable across the Westminster-tradition public sector (CA, AU, IE, UK). This article maps each of the six commitments (Transparency, Partnership / Te Tiriti, People, Data, Privacy / Ethics / Rights, Human Oversight) to deliverable architectural artefacts (algorithm register, model card, DPIA, iwi engagement record, TMR plan, affected-people impact narrative, audit log, oversight thresholds, explainability report). Includes the artefact register pattern, 8 anti-patterns, and the 5-stage maturity ladder.