Email Verifier API Verification

Real-time email-address verification endpoint. Single resource at https://emailverifierapi.com/v2/ accepting GET or POST. Returns a top-level deliverability status (passed / failed / unknown / transient), a granular event code (mailboxExists, mailboxDoesNotExist, mailboxIsFull, domainDoesNotExist, mxServerDoesNotExist, invalidSyntax, isCatchall, isGreylisting, transientError), and a set of intelligence flags (isDisposable, isRoleAccount, isFreeService, possibleSpamtrap, isComplainer, isOffensive, isGibberish), along with the MX server IP and ISO country, a typo-corrected address suggestion, the remaining credit balance, and the wall-clock execution time. Authentication is by API key passed as the `apiKey` query parameter.