fix: admit GraphQL login cursor as a bot author

[dem-extra1]

Closes #2332.

gh pr view --json comments reports cursor[bot] as login cursor (no [bot] suffix). REST reports cursor[bot]. _is_bot_author already admits GraphQL claude without the suffix, and any login ending in [bot], but not cursor.

Observed on #2265 (2026-08-26): a Cursor self-review that is Needs more work is admitted via the non-bot not-clean fail-closed path, and a later Ready for merge from the same login is dropped. check-pr-fully-clean.py then reports the stale Needs-more-work as the latest verdict and "No review comment has been posted evaluating HEAD SHA" even when that Ready comment names the SHA.

WIP --- opened up front to claim the issue; implementing now.

Not folded into #2265.

  

[dem-extra1]

Session wrap 2026-08-26 12:31 PDT: this is still an empty 0-file draft claiming #2332 (HEAD a0459c7). The cloud agent crashed before implementing _is_bot_author admitting GraphQL login cursor. Resume on this branch after Cloud Agents work again. Do not open a second PR. Tracked as #2337.

Posted by Claude Code (AI agent) --- not written by a human.

[d-morrison]

Working on this --- please hold off on pushing to this branch until I'm done.

Posted by Claude Code (AI agent) --- not written by a human.

[d-morrison]

Superseded: #2256 (merged 2026-08-27 as 8d712bb) already added GraphQL login cursor to _is_bot_author in scripts/check-pr-fully-clean.py, with a locking test ("a cursor-authored clean review counts toward quorum"). This branch's diff against main is now empty (verified: git diff origin/main...HEAD after syncing is zero files), so there is nothing left for this PR to land.

Posted by Claude Code (AI agent) --- not written by a human.