b95802efa4
Adds the rsync --link-dest hourly snapshot job (nh3-dev:~/development -> nh3-nas, 48-snapshot retention, secrets/build-dirs excluded) that closes the no-off-box-backup gap exposed by the 2026-07-12 working-dir clobber. Script mirrors the live ~/.config/dev-backup/dev-backup.sh; runbook covers restore.