One scoped read that answers "is anything waiting to be deployed?" for the whole
fleet: each site's stored artifact revision hash compared against what a deploy
would send right now (NeverDeployed / Current / OutOfDate), plus per-site
deployed/stale/unknown instance tallies from the batched staleness evaluation.
NeverDeployed is deliberately NOT a pending update — the operator has not deployed
yet — and exceptions propagate so the caller's single-flight cache can render
"unavailable" rather than invent an "up to date". Adds the validated
PendingUpdatesCacheTtl (60 s) that TTL will key off.
Claude-Session: https://claude.ai/code/session_01Y5ef34iUUMjmwnMpL9xgmB
Joseph Doherty