Pipeline 2562: the shell chain now reaches the preflight suite and dies at 'mktemp: : Invalid argument' — the CI image's mktemp dialect rejects 'mktemp -u /tmp/...XXXXXX.sock' (GNU accepts it locally, which is why the suite passed on dev hosts only). The path is now composed (/tmp/mosaic-preflight-$RANDOM-$$.sock): short enough for the 108-byte AF_UNIX bind limit (a repo-deep path fails with 'path too long', measured), unique per run, no pre-existing file, cleaned by the existing trap. Verified locally: suite passes, no /tmp residue.