[安全性] 通过注册表 Web 钩子列表中的 sort_order 进行盲目 SQL 注入

The sort field is allowlisted but the order is not. `SortOrder` is generated by oapi-codegen as a plain `type SortOrder string` with no runtime enum validation, so any bytes survive. Every sibling controller normalizes with `GetSortByOrder()` (`metadata/utils.go:220`, coerces to ASC/DESC); this is the one call path that skips it. `upstream_proxy.go:338` interpolates the same pair, so the caller-side fix alone leaves a second risky path.