get_diagnostics_overview

Return an account-health summary: what is wrong or about to go wrong at the billing/account level. Returns {unpaidInvoices:{count, totalUnpaid, invoiceIds, earliestDue}, expiringServices:[], expiringDomains:[], suspendedServices:[], windowDays, checkedAt} — unpaid invoices, services and domains expiring within ~30 days, and suspended services. This is the account/billing side only — for disk/dns/tls symptom triage on one site use diagnose; for the setup checklist of a new account use get_onboarding_next_steps; to see individual invoices use list_invoices. Everything returned is this account's own data.