Operational validation of Geo support for OpenBao on GitLab CNH

Summary

Validate Geo support for OpenBao on Cloud Native Hybrid (CNH) GitLab.

This is a follow-up issue to Operational validation for Cloud Native Hybrid ... (#568357 - closed).

Scope

This issue tracks validation of:

1. Geo replication compatibility - Ensure OpenBao can be deployed on both primary and secondary Geo sites
2. Data synchronization - Verify that secrets and credentials are properly synchronized (or isolated) between Geo sites as appropriate
3. Failover scenarios - Test failover from primary to secondary site with OpenBao enabled
4. Recovery scenarios - Test recovery from secondary to primary site with OpenBao enabled
5. Multi-site authentication - Validate JWT authentication and credential provisioning work across Geo sites
6. Database consistency - Ensure OpenBao's PostgreSQL storage remains consistent in Geo replication

Acceptance Criteria

• OpenBao deploys successfully on both primary and secondary Geo sites
• Secrets provisioned on primary site are accessible on secondary site (if applicable)
• Failover from primary to secondary works with OpenBao enabled
• JWT authentication continues to work after Geo failover
• No data loss or corruption in OpenBao database during Geo replication
• Documentation updated with Geo-specific deployment instructions (if needed)
• Update https://docs.gitlab.com/charts/charts/openbao/#known-issues