Documize Community's attachment download route (domain/attachment/endpoint.go, Download function, registered via AddPublic with no auth middleware) accepts a query parameter and grants access wheneve…

摘要

Documize Community's attachment download route (domain/attachment/endpoint.go, Download function, registered via AddPublic with no auth middleware) accepts a query parameter and grants access whenever the parameter is simply non-empty (len(secureToken) > 0), without comparing it to any server-stored value.

中文摘要建设中，暂以英文摘要呈现（DR-003 v2）。