bdb8431773
- Added verifyAllPaymentsCompleted() helper in MenuHelper.h to check if the authenticated customer has completed all invoices. - Integrated payment verification into CustomerMenu::selectService() to block new service bookings when pending payments exist. - Integrated payment verification into CustomerMenu::selectComboPackage() to block new combo package bookings when invoices are incomplete. - Implemented iteration over customer invoices to ensure only users with all payments marked as COMPLETED can proceed with new bookings. - Added user-facing messages to inform customers when bookings are denied due to outstanding payments. Fixes #2116