add backup_output_bytes metric and cloudsync_transferred_bytes to backup dashboard
- All 7 backup CronJobs now push backup_output_bytes (file size after backup)
- Cloud Sync monitor parses rclone transfer stats into cloudsync_transferred_bytes
- Grafana dashboard: new Output (MiB) table column, Output Size Trend panel,
Write Throughput panel, Cloud Sync Transfer Volume bargauge
- All timeseries panels use points-only draw style (discrete backup snapshots)
- etcd backup restructured: init_container for etcdctl (distroless image),
busybox sidecar for metrics push + purge, ClusterFirstWithHostNet DNS
- Fixed pre-existing curl missing in postgres:16.4-bullseye (immich, dbaas PG)
- Fixed grep -oP not available in alpine/busybox (cloud sync monitor)
d20c5e5535