fix(models): sub_distributors created_at/updated_at 去掉带引号的 CURRENT_TIMESTAMP default

default: "CURRENT_TIMESTAMP" 让 json2ddl 生成 DEFAULT 'CURRENT_TIMESTAMP'(带引号),
MySQL 报 Invalid default value for created_at，导致建表中断(11张表未建)。

models/sub_distributors.json

@@ -111,14 +111,12 @@
       "name": "created_at",
       "title": "创建时间",
       "type": "datetime",
-      "nullable": "no",
+      "nullable": "no"
-      "default": "CURRENT_TIMESTAMP"
     },
     {
       "name": "updated_at",
       "title": "更新时间",
-      "type": "datetime",
+      "type": "datetime"
-      "default": "CURRENT_TIMESTAMP"
     }
   ],
   "indexes": [