Add accounting.recurring_templates (bill|journal) with a schedule
(frequency/interval/day-of-month/start/end). New generate_due_recurring()
materialises real bills (-> A/P) and journal entries on cadence — catching
up any missed periods — posting through existing triggers. Runs nightly via
pg_cron ('accounting-recurring-daily') and on demand from a new Recurring
page ('Generate due now'). Page lists templates with pause/resume/edit/
delete; create dialog handles both kinds (vendor + line items for bills,
signed balanced lines for journals). Wired into routes + accounting nav.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
