Collapse historical duplicate comments produced before the 60-second
dedupe guard landed. Keeps the earliest row in each cluster, reparents
nested replies onto it, moves comment_likes rows, deletes the rest.
Default --window=60 matches the server guard; --dry-run shows the plan
without touching the DB. Transactional per group so a partial failure
does not leave orphaned likes.
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
