fix(product): 修复产品库存数据处理中的空值问题

- 为 cost_price 字段添加空值合并操作符，避免空值导致的错误
- 添加 sku_id 和 spec_id 字段的空值处理，确保数据完整性
- 优化库存数据结构，提高数据处理的稳定性

app/common/repositories/store/product/ProductRepository.php

@@ -463,7 +463,7 @@ class ProductRepository extends BaseRepository
                         "sku"           => $sku,
                         "unique"        => $unique,
                         "dacang_price"  => $value['dacang_price'],
-                        "cost_price"    => $value['cost_price'],
+                        "cost_price"    => $value['cost_price'] ?? 0.00,
                         "gong_sku_id"   => $value['gong_sku_id'],
                         "pension_num"   => 0,
                         "share_num"     => 0,
@@ -473,6 +473,8 @@ class ProductRepository extends BaseRepository
                         'gong_mer_profit' => $value['gong_mer_profit'] ?? 0.00,
                         'gong_market_price' => $value['gong_market_price'] ?? 0.00,
                         'plate_mer_profit' => $value['plate_mer_profit'] ?? 0.00,
+                        'sku_id' => $value['sku_id'] ?? null,
+                        'spec_id' => $value['spec_id'] ?? null,
                     ];
                 } else {
                     $result['attrValue'][] = [