Move backup from a documented procedure to `deploy/backup.sh`: dumps Postgres
(pg_dump --clean --if-exists, gzipped) and archives the MinIO /data directory
into a single timestamped bundle under backups/. Reads config from the compose
.env with the same defaults the stack uses; optional BACKUP_RETAIN_DAYS prunes
old bundles (cron-friendly). BACKUP.md documents usage + the restore procedure
(kept manual/documented rather than an untested destructive script).
Closes#196
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Justin Paul <justin@jpaul.me>
