Fixes from an independent correctness review: VAT rounding on the VAT component, ISO 4217 minor units (KWD, JPY and others), prototype-safe grouping, mileage currency guard, explicit rebill marking scoped per currency, invoice line totals reproduce receipt gross, office-suite proxy drains child stderr and reports license activation per child. Built by theluckystrike. Pro keys: https://mcp.zovo.one