PostgreSQL does not support IF NOT EXISTS for ADD CONSTRAINT. Use PL/pgSQL
DO blocks to guard constraint creation idempotently instead.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Adds invoice_payment, recurring_invoice, recurring_invoice_item tables and
publicToken/lastReminderSentAt/invoicePrefix columns to invoice. Uses
IF NOT EXISTS guards since invoicePrefix may have been applied via db:push.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>