Covers DeleteCustomer (success + NOT_FOUND no-op), doJSON truncation (oversized bodies + rune-safe capBody), validCardID rejection without leaking the token, paymentFromSquare empty-card consistency, and mock-side customer-ID redaction in logs.
Covers DeleteCustomer (success + NOT_FOUND no-op), doJSON truncation (oversized bodies + rune-safe capBody), validCardID rejection without leaking the token, paymentFromSquare empty-card consistency, and mock-side customer-ID redaction in logs.