docs(backup): record minio versioning and lifecycle policy

TOOLS.md

@@ -92,6 +92,15 @@ Skills are shared. Your setup is yours. Keeping them apart means you can update
 - Endpoint: `http://192.168.153.253:9000`
 - Bucket: `zap`
 - Credentials file: `~/.openclaw/credentials/minio-zap.env` (mode `600`)
+- Backup script: `scripts/backup-to-minio.sh`
+- Backup scope: full archive of `~/.openclaw` (tar.gz) + `sha256` + `manifest.txt`
+- Backup schedule: system cron every 6 hours at minute 17
+  - `17 */6 * * * /home/openclaw/.openclaw/workspace/scripts/backup-to-minio.sh >> /home/openclaw/.openclaw/workspace/memory/minio-backup.log 2>&1`
+- Bucket versioning: enabled
+- Lifecycle rule (prefix `workspace-backups/`):
+  - expire noncurrent versions after 90 days
+  - keep 3 newer noncurrent versions
+  - expire delete markers enabled
 
 ### Kubernetes (homelab)