fix(after-sale): 售后工单已完结仍可再次申请，改由订单是否已退款决定

上一个提交把「工单 completed」当成了不能再申请售后的判据，方向搞反了：
能否再售后应该看订单有没有被标「已退款」，而不是看工单状态。订单已退款时
status_group 变成 refunded、enabled 直接为 false，那道闸门本来就够用；用工单
状态再判一次，反而把「工单已完结但订单没退款」的用户堵死，售后详细弹窗底部
也只剩下一个「我知道了」死胡同。

- reapplyable_statuses 补上 STATUS_COMPLETED：rejected / cancelled / completed
  一律放行再次申请，售后详细弹窗底部按钮对已完成订单渲染「再次申请售后」
- can_apply 还原为只看有没有进行中的工单（!open），不再二次校验工单状态
- create() 的重复申请闸门还原为 find_active()：只挡仍在流转的工单，
  completed 不挡；订单已退款由上面的 STATUS_PAID 校验先挡掉
- 点「再次申请售后」后清 has_application 落回申请表单，提交走 create()
  新建工单，链路本来就通，无需改动

harness 场景名改为 settled_ticket_still_allows_reapply，断言 completed /
rejected / cancelled 三种已终结状态都能新建工单；待审核工单同因幂等、换因
挡住的场景保留。

验证：tests/widget-system/ 462 项、tests/admin/ 76 项通过；after-sale-log-harness
7/7。未做浏览器视觉验收。

tests/widget-system/order-after-sale-assets-contract.test.cjs

@@ -63,15 +63,12 @@ test('after-sale submissions are order-locked and admins set status directly', (
     assert.ok(!column.includes(dead), `${dead} column must be removed from aksrt_order_aftersale`)
   }
   // create() 的重复申请闸门看「最新一条工单」而不是只看进行中的：已完结同样要挡
-  assert.match(afterSale, /GET_LOCK\(%s, 5\)[\s\S]*?get_user_order\(\$user_id, \$order_number\)[\s\S]*?latest_for_order\(\$order_number\)/)
-  assert.ok(afterSale.includes("return new \\WP_Error('aksrt_after_sale_exists', __('该订单的售后申请已完结，不能再次申请', 'aksrt'), ['status' => 409]);"),
-    'completed ticket must block a new application')
-  // 待审核 / 处理中仍走同人同因幂等，rejected / cancelled 放行再次发起
-  assert.match(afterSale, /in_array\(\$latest_status, \[self::STATUS_PENDING, self::STATUS_PROCESSING\], true\)/)
-  assert.match(afterSale, /hash_equals\(\(string\) \(\$latest\['reason'\] \?\? ''\), \$reason\)/)
-  // 只看 create() 方法体，避免跨方法匹配到 cancel_for_user() 里的 find_active
-  const createBody = afterSale.slice(afterSale.indexOf('public function create('), afterSale.indexOf('private function sanitize_images('))
-  assert.ok(!createBody.includes('find_active'), 'create must not gate on find_active alone')
+  // 只挡仍在流转的工单：已完结（completed）不挡，能否再售后由订单是否已退款决定
+  assert.match(afterSale, /GET_LOCK\(%s, 5\)[\s\S]*?get_user_order\(\$user_id, \$order_number\)[\s\S]*?find_active\(\$order_number\)/)
+  // 待审核 / 处理中：同人同因幂等返回原工单
+  assert.match(afterSale, /hash_equals\(\(string\) \(\$active\['reason'\] \?\? ''\), \$reason\)/)
+  // 订单已退款走 STATUS_PAID 校验挡掉，工单 completed 不参与这道闸门
+  assert.ok(!afterSale.includes('该订单的售后申请已完结，不能再次申请'), 'completed-block copy must be removed')
   assert.match(afterSale, /Order::STATUS_PAID/)
   assert.match(afterSale, /public function set_status\(int \$id, string \$status, string \$note = ''\)/)
   assert.match(afterSale, /in_array\(\$status, \[self::STATUS_PENDING, self::STATUS_PROCESSING, self::STATUS_COMPLETED, self::STATUS_REJECTED, self::STATUS_CANCELLED\], true\)/)