[IC-089] Implement encrypted automated backups and prove restore in an isolated environment.

[github-actions]

Outcome

Implement encrypted automated backups and prove restore in an isolated environment.

Acceptance checks

• RPO/RTO are documented; restore drill validates database/object consistency and tenant access; results are retained.

Dependencies

IC-060

Planning metadata

• Priority: P0
• Milestone: Milestone 9 — Operations and pilot readiness

Definition of done

• Automated tests cover the change where practical.
• Tenant/environment isolation and failure paths were reviewed.
• Logs and errors contain no secrets, PII, documents, or biometric data.
• Relevant API, architecture, operations, and user documentation is updated.
• The pull request links this issue and lists verification commands.
  Generated from docs/planning/implementation-backlog.md; edit the backlog and rerun the sync to change generated fields.