sync-upstream.yml, sync-rebuilds.yml and track-branches.yml each opened one
batch PR, so one package with a failing build held back every other update
in it (#788, #837). All three now group their changes with
package-pr-groups.sh and hand them to package-prs.yml, which opens a PR per
package and arms auto-merge. Packages pinned from the same upstream branch
still share one. Green packages land on their own and only the failures stay
open; a red PR conflicting with master, and each lane's old batch PR, get
closed.
sync-upstream.yml loses its human-merged lane: it now pushes with the PAT
like the other two, so its builds start without an approval hold and its PRs
auto-merge when green. min_release_age still quarantines fresh releases. Its
approve job, approve-sync-push.cjs, and auto-merge-pr.cjs's exception for
auto/sync-upstream go with it.