feat(sprint8): Phase 1 — Treasury backend (fee schedules, payments, Kassenbuch)
- Extend StaffPermission with MANAGE_FINANCES, VIEW_FINANCES
- Extend AuditEventType with PAYMENT_RECORDED, PAYMENT_VOIDED, FEE_SCHEDULE_CREATED, FEE_SCHEDULE_UPDATED, EXPENSE_RECORDED
- Extend NotificationType with PAYMENT_REMINDER, PAYMENT_OVERDUE, PAYMENT_RECEIVED
- New enums: PaymentMethod, PaymentStatus, TransactionType, FeeInterval, ExpenseCategory
- V18 Flyway migration: fee_schedules, member_fee_assignments, payments, ledger_entries tables
- Entities: FeeSchedule, MemberFeeAssignment, Payment, LedgerEntry
- Repositories with financial queries (balance, outstanding, period sums)
- FinanceService: fee schedule CRUD, record/void payments, expenses, Kassenbuch, summaries
- FinanceController: 14 admin endpoints + 2 portal self-service endpoints
- LedgerEntry is append-only per §147 AO (no update/delete)
- All amounts in cents (Integer) to avoid floating-point precision issues
Patrick Plate
721503b231