docs(jangar): record post-merge rollout risk

[gregkonush]

Summary

• Updates the Jangar release handoff with post-merge stability evidence from the final rollout window.
• Records docs(jangar): refresh control plane release gate #5518 as merged and corrects the active Jangar pod evidence from the initial healthy snapshot.
• Documents the app restart count, database migration timeout exits, recurring DB readiness warning, and rollback trigger.

Related Issues

None

Testing

• PASS: bunx oxfmt --check docs/agents/release-handoffs/jangar-control-plane-verify-2026-05-05.md
• PASS: git diff --check
• PASS: bun run build:docs

Screenshots (if applicable)

N/A. Documentation-only release handoff.

Breaking Changes

None.

Checklist

• Testing section documents the exact validation performed (or N/A with justification).
• Screenshots and Breaking Changes sections are handled appropriately (removed or filled in).
• Documentation, release notes, and follow-ups are updated or tracked.

[gregkonush]

Status: ready as of 2026-05-05T17:41Z. This follow-up PR corrects the durable handoff with the post-merge stability evidence: Jangar remained Argo Healthy and 2/2 Ready, but the app had two migration-timeout restarts and DB readiness warnings recurred.

• Local validation passed: bunx oxfmt --check docs/agents/release-handoffs/jangar-control-plane-verify-2026-05-05.md, git diff --check, and bun run build:docs.
• feat(jangar): surface failure-domain lease holdbacks #5454 remains unmerged and blocked by the required large-diff Codex review usage-limit response.
• Rollout gate for feat(jangar): surface failure-domain lease holdbacks #5454 should include a clean Jangar/DB stability window before any future merge.

Gate for this PR: wait for GitHub checks to finish, then merge if green and review-clean.