[feat] Backport graceful shutdown rollout

[Al-assad]

Summary

• Backport graceful shutdown rollout from branch-25.8.0 into master.
• Add sentinel compatibility gate: only images whose BE entrypoint supports the terminating sentinel contract use graceful rollout; unsupported images fall back to the existing StatefulSet flow.
• Keep master-side behavior for internal/external services, storage template immutability, readiness probe policy, TLS/mTLS readiness, and podinfo volume mount drift fixes.

Validation

• go test ./pkg/common/utils/resource ./pkg/controller/sub_controller/disaggregated_cluster/computegroups ./pkg/controller/sub_controller/disaggregated_cluster/disaggregated_fe ./pkg/controller/sub_controller/disaggregated_cluster/metaservice
• make manifests
• git diff --cached --check