Complete with requirements in view

What changes

• When completing a task, required items stay visible and optional items stay collapsed. Each service defines whether payment must be resolved before completion. Partial payment can leave the rest as debt; fully paid tasks need no further payment decision.
• Staff may leave debt only when the customer has a credit limit and the resulting balance stays within it. Owners and managers can authorize debt. Project settings provide the initial value for new services; each service retains its own rule. Canceling the sheet does not complete the task or record payment.
• QR/link completion awaits integration and will not complete before payment confirmation.
• Even when a service allows payment later, staff without enough credit capacity see the required payment step before completing. No-shows do not count as debt, and their deposits remain retained.