fix(worker-platform): 修复售后欠款抵扣导致验收失败，并支持余额偿还

有待还欠款时结算写入 settled_at 发生 timestamptz/text 类型错误会整单 500；顺带支持充值/解冻自动偿还与后台手动偿还。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/backend/src/routes/admin/worker-platform/after-sales.ts

@@ -4,6 +4,7 @@ import {
   createAdminAfterSalesCase,
   getAdminAfterSalesCaseEvents,
   listAdminAfterSalesCases,
+  repayAdminAfterSalesCaseDebt,
   resolveAdminAfterSalesCase,
 } from '../../../services/worker-platform/index.js'
 import { createJsonHandler, requireAdminRoles } from '../session.js'
@@ -78,4 +79,28 @@ router.post(
   ),
 )
 
+router.post(
+  '/worker-platform/after-sales-cases/:caseId/repay',
+  requireAdminRoles(['admin', 'operator', 'support']),
+  createJsonHandler(
+    (req) =>
+      repayAdminAfterSalesCaseDebt(
+        String(req.params.caseId || ''),
+        req.body || {},
+        req.adminSession?.username || '',
+      ),
+    {
+      successMessage: '售后欠款已偿还',
+      errorMessage: '偿还售后欠款失败',
+      scope: '[admin/worker-platform/after-sales-cases/:caseId/repay]',
+      audit: (req, data) => ({
+        action: 'after_sales_case_debt_repaid',
+        targetType: 'after_sales_case',
+        targetId: String(req.params.caseId || ''),
+        data: data && typeof data === 'object' ? (data as Record<string, unknown>) : {},
+      }),
+    },
+  ),
+)
+
 export default router