ICYLAB Billing v6.17 - Controlled Bulk Payments

Production bulk collections and payments remain active only when:
- production READ gate is enabled
- production FINANCE gate is enabled
- production ISSUE gate remains disabled
- the authenticated user has the exact bulk permission

Safety controls:
- existing CxC/CxP required
- immutable selection snapshot
- expected balance and due date validation
- deterministic allocation by due date
- transaction row locks
- atomic all-or-nothing write
- production idempotency
- duplicate reference protection
- future payment date blocked
- production audit reference required
- 100 documents maximum per batch
