auto_update::run now calls meta::lock_update_hyperhive once
up-front so the per-agent rebuilds it kicks off rebuild against
the new base. lifecycle::rebuild already drives sync_agents +
lock_update_for_rebuild per agent, so the rev-marker shortcut
keeps its meaning ('we've ack'd this rev for this agent')
without further plumbing. failures of the hyperhive lock bump
log + continue — individual rebuilds will surface concrete
errors if anything's really wrong.
approval grows fetched_sha (canonical hive-c0re-vouched sha,
distinct from manager-supplied commit_ref). helperevent
{approvalresolved,spawned,rebuilt} grow optional sha + tag so
the manager can git-show the exact tree it's hearing about
(against the upcoming /agents/<n>/applied.git RO mount) and
know which terminal tag landed. all serde-defaulted; existing
construction sites pass none until the tag-driven flow lands.
