Auto-fix 862 lint errors: convert value imports used only as types to
`import type`, fix import group ordering in seed.ts and du-an-api.ts,
remove unused imports in auth controller, and clean up stale eslint-disable
comments referencing non-existent rules.
Co-Authored-By: Paperclip <noreply@paperclip.ing>
Add BANK_TRANSFER as a fully supported payment provider:
- BankTransferService implementing IPaymentGateway with HMAC-SHA256 verification
- ConfirmBankTransferCommand/Handler for admin manual payment confirmation
- POST /payments/:id/confirm-transfer admin endpoint (RBAC-protected)
- Atomic status updates with idempotency (PENDING/PROCESSING → COMPLETED)
- Registered in PaymentGatewayFactory alongside VNPAY, MOMO, ZALOPAY
- Comprehensive unit tests for service and handler
Co-Authored-By: Paperclip <noreply@paperclip.ing>
