Feat/188 automated backup recovery

[mijinummi]

Automated Backup and Disaster Recovery System (#188)

Objective

• Implement automated database backups, PITR, and disaster recovery procedures.

Changes

• Added cron jobs for hourly/daily backups.
• Implemented PITR with WAL logs.
• Added backup encryption (AES-256).
• Added retention policy.
• Added monitoring and alerting hooks.
• Added restoration testing schedule.
• Added Jest tests for backup service.

Acceptance Criteria

• ✅ Backups run automatically.
• ✅ PITR functional for 30 days.
• ✅ Restoration tested regularly.
• ✅ Alerts sent on backup failures.
• ✅ Encryption secures backup data.
• ✅ Tests verify backup integrity.
  Closes Automated Backup and Disaster Recovery System #188