## 1. Implementation

- [x] 1.1 Update refund detail to render voucher images inline when voucher keys exist.
- [x] 1.2 Add click-to-preview/enlarge behavior for refund detail voucher images.
- [x] 1.3 Add `payment_status: 2` to the order number search/select request used by create refund application.
- [x] 1.4 Update refund management voucher upload to allow multiple image uploads.
- [x] 1.5 Submit uploaded voucher file keys joined by English commas in `refund_voucher_key`.
- [x] 1.6 Validate that at least one voucher image is uploaded before submission when voucher is required.
- [x] 1.7 Verify refund detail display, order selector filtering, and multi-image payload behavior.
- [x] 1.8 Allow requested refund amount `0` while blocking negative and over-actual amounts.