Multi-region routing and failover behavior

[sebastienrousseau]

User Story

As a global platform operator, I want multi-region routing and failover behavior, so that regional incidents do not cause broad outages.

Acceptance Criteria

1. Given multiple healthy regions, when requests are routed, then traffic follows configured regional policy.
2. Given a region becomes unhealthy, when failover policy triggers, then traffic shifts to healthy regions.
3. Given failover completes, when service is monitored, then user-visible availability stays within target.
4. Given region recovers, when recovery policy is applied, then traffic rebalancing is controlled and observable.
5. Given multi-region configuration is invalid, when validation runs, then deployment is blocked with diagnostics.

[sebastienrousseau]

Triage owner suggestion: Global Traffic and Failover Team.\n\nRationale: this issue’s primary outcomes align with this ownership area.