fix(funds): 加固转账冲正、结算收付幂等与坏账核销

- 转入 main_site_timeout 等不可冲正场景直接拒绝，避免假结案
- payment_records / settlement_adjustments 增加 partial unique 索引
- 坏账核销行锁 + meta 幂等回放；补差单记录 result_bill_id
- 新增 FundOperationsHardeningTest 覆盖关键路径

app/Support/AdminTransferOrderCapabilities.php

@@ -32,9 +32,7 @@ final class AdminTransferOrderCapabilities
         $canWrite = self::canWriteWallet($admin);
 
         return [
-            'can_reverse' => $canWrite
-                && $order->status === 'pending_reconcile'
-                && ($order->direction === 'out' || $transferService->isEligibleForTransferInReverse($order)),
+            'can_reverse' => $canWrite && $transferService->isEligibleForReverse($order),
             'can_complete_credit' => $canWrite
                 && $order->direction === 'in'
                 && $order->status === 'pending_reconcile'