fix: 修正产品规格值product_spec的显示问题

- subItem.value => subItem.key
- 调整后端CMS的结构，将规格值移入translations中

app/composables/directus/useProduct.ts

@@ -34,9 +34,8 @@ export const useProduct = (id: string) => {
                 specs: [
                   'id',
                   {
-                    translations: ['id', 'key'],
+                    translations: ['id', 'key', 'value'],
                   },
-                  'value',
                 ],
               },
             ],