- Search now shows ALL active participants (not just those with existing invoices)
- Auto-generates renewal invoices on-the-fly when participant has overdue billing
- Radio buttons use wire:model.live for immediate state update (fixes Next button)
- Upcoming renewals section shows "Generate Invoice" button as fallback
- Next button always visible (disabled until invoice selected)
- Advances next_billing_date after generating renewal invoice
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>