feat: 备货单 detail 接口车辆列表补充返回 attachment

prepareVehicleListData 组装每辆车时带上 attachment（模型 array cast
取出即 [{url, original_name}]）；同款车按 unique_id 合并的行，
各车附件按 url+文件名并集去重后拼接。show 接口本就带，不动。

Co-Authored-By: Claude <noreply@anthropic.com>

app/common/service/StockOrdersService.php

@@ -884,6 +884,18 @@ class StockOrdersService
                         $vehList[$v->unique_id]['remark'] = $v->remark;
                     }
                 }
+                // 拼接附件（并集去重，按 url+文件名）
+                $currAttach = is_array($v->attachment) ? $v->attachment : [];
+                if (!empty($currAttach)) {
+                    $union = [];
+                    foreach (array_merge($vehList[$v->unique_id]['attachment'], $currAttach) as $a) {
+                        $key = ($a['url'] ?? '') . '|' . ($a['original_name'] ?? '');
+                        if (!isset($union[$key])) {
+                            $union[$key] = $a;
+                        }
+                    }
+                    $vehList[$v->unique_id]['attachment'] = array_values($union);
+                }
                 continue;
             }
             $index++;
@@ -899,6 +911,7 @@ class StockOrdersService
                 'mileage' => $v->mileage,
                 'remark' => $v->remark,
                 'vin' => $v->vin,
+                'attachment' => is_array($v->attachment) ? $v->attachment : [],
             ] + $moneyValues;
         }
         return ['list' => $vehList];