Frontend half of #1806 (batch start has no visible running-action feedback).
damocles is routing dashboard start/hard-stop through the rebuild queue as
QueueKind::Start ('start') / Stop ('stop') so they get the same async
queued->running card progression as restart/rebuild/graceful-stop (the sync
transient_guard flash is too brief to see, esp. in a sequential bulk loop).
This adds the row-renderer label cases: 'start' -> starting/start queued,
'stop' -> stopping/stop queued (mirrors the graceful_stop case from #1791).
Forward-compatible: no-op until the backend emits those kinds. Doc updated.
3a2cdaa37b