Simplify E2E Failure List Join

rly? https://github.com/entireio/cli/pull/1577#discussion_r3498492382 fix it on that branch if so.
No — false positive. Nothing to fix.
Bugbot's claim is that "GNU paste exits non-zero when it receives no lines," which would abort the set -euo pipefail step. I verified that's wrong:
- GNU coreutils 9.8
paste -sd, -on empty input → exit 0, empty output. - The full pipeline
echo $red | tr ... | sed ... | paste -sd, - | sed ...with emptyredunderpipefail→ exit 0,out=[]. - BSD
paste(macOS) behaves identically.
The empty-list case is actually the normal path (e.g. cursor-cli-only failure → red empty, yellow set). If paste failed here, the yellow-only Slack alert would never work at all. It works fine.
Left the branch untouched.
Done — committed on magical-yawning-matsumoto.
Change: replaced the tr | sed | paste -sd, - | sed chain with bash parameter expansion:
Strip the leading space, substitute , for spaces. Verified identical output for empty / single / multi cases. No subprocesses, nothing to abort under pipefail. Not pushed.