Replace single daily schedule (240h TTL) with three tiered schedules:
- daily-backup: 02:00 nightly, 192h TTL → keeps last 7 daily backups
- weekly-backup: 03:00 Sundays, 1032h TTL → keeps last 6 weekly backups
- monthly-backup: 04:00 on 1st, 4392h TTL → keeps last 6 monthly backups
Kopia handles incremental deduplication at the block level automatically,
so each Velero backup only stores changed data despite being a full logical
snapshot. No additional incremental configuration required.
Update README with retention policy table and updated backup commands.