The workspace-update qualification runner still copied lib/preload.cjs after the standalone management preload and its build entry were removed. A clean Desktop build emits only the application, mandatory-update, and update-dialog preloads, so qualification failed with ENOENT before Electron could start; stale outputs could conceal that failure.
Remove only the obsolete copy-list entry. Keep all three current preloads required and retain ordinary copy failures. Executing the actual copy loop against artifacts from a fresh isolated Desktop build now copies exactly those three files byte-for-byte while lib/preload.cjs is absent; the same loop failed at that missing file before this change.