Update OpenBao 0.6.1 consumption and upgrade guidance

Problem

The self-managed stack and release documentation do not fully consume or explain the remediated OpenBao image set. The stack still selects chart 0.30.23, which uses OpenBao 2.5.4-nv-1.3.0, while the remediated chart is 0.30.25 with OpenBao 2.5.5-nv-1.3.1 and migrations 0.16.2.

Existing OpenBao server pods also use an OnDelete StatefulSet strategy. Updating the Helm release changes the pod template but does not restart running server pods.

Desired outcome

• Pin the self-managed stack to OpenBao chart 0.30.25.
• Document the 0.6.0 to 0.6.1 OpenBao upgrade sequence.
• Tell operators to verify the migration Job and rotate standby pods before the active pod.
• Preserve OpenBao persistent volume claims during the rotation.

Start by locating the self-managed stack's Helm chart pin and the release documentation covering OpenBao upgrades. Compare the current 0.30.23 selection with the requested 0.30.25 chart, OpenBao 2.5.5-nv-1.3.1, and migrations 0.16.2. Done means the upgrade sequence explains migration verification, standby-before-active rotation, and persistent volume claim preservation.