554d273cf5
Cloned images were unreachable via GET /knowledge-bases/:id/files:
copyOwnedObject used CopyFile, which writes to the knowledge-scoped upload
layout ({tenant}/{knowledgeID}/...), but the KB proxy only serves objects
under {tenant}/exports/ (ValidateKBScopedStoragePath). Read the source
bytes and re-save via SaveBytes instead, mirroring how images are
persisted during ingestion, so copies land in the servable exports
namespace and remain independent of the source object.