Changes

ci(flaky-tests): sync GitHub issues and update report (#4296)

## Summary
- add GitHub issue sync for flaky reporter
(search/create/reopen/labels/comments) with configurable mutation limit
and comment toggle
- update report rendering (issue column merge, WoW icons/colors, column
order)
- enable issue sync + comment in periodic job and remove set -x
- harden issue ops (token required for mutations, repo validation,
GitHub API retry/backoff)

## Testing
- Not run (not requested)
 (commit: dad5930)