The finalized-issue boilerplate promises "reopen and I'll triage again from
scratch," but github_events.route() dropped issues.reopened to the ignored
skip branch (only opened/closed handled), while pull_request.reopened was
already routed. A user following the instruction got silence.
Route issues.reopened like issues.opened (submitter-attributable triage_issue,
same per-user rate budget) and dispatch it in queue._dispatch(). triage_issue
now tears down a stale finalized workspace (merged/closed/abandoned) before
re-provisioning, mirroring the maintainer directive-reopen teardown so the
re-triage branches afresh from default instead of a merged/deleted branch.
Fixes#5891
roboomp
3967ad0d5d