Test OpenBao / Geo Integration on GDK

Why are we doing this work

This issue tracks the integration of OpenBao Geo for disaster recovery. The work involves ensuring OpenBao can properly replicate data across Geo sites using PostgreSQL replication, handle failover scenarios, and maintain secrets availability during Geo site promotions.

This integration is critical for self-managed GitLab deployments and GitLab Dedicated that rely on Geo for geographic distribution and disaster recovery.

Outcome

Testing has been completed using GDK to validate that OpenBao works correctly with Geo's PostgreSQL replication and automatic failover mechanisms. #485595 (comment 2746197130)