feat: apply DELTA.md changes and add status file contracts

[sujit-jadhav]

Summary

• Apply 13 changes from DELTA.md to align orchestrator with staging branch
• Add status file contracts for discovery and orchestrator domains

DELTA.md Changes

1. NVIDIA driver per-arch (nvidia-driver version configurable #4845) — configurable driver versions per architecture
2. etcd user/group creation (Update etcd-fstab-update.sh.j2 #4839) — ensure etcd user/group exist before chown
3. first FG name fix (Fix: Additional cloud init support for kube control plane first #4863) — handle first suffix in functional group matching
4. Multi-subnet Calico CIDRs + kube-vip — compute CIDRs from all K8s node subnets
5. NFS SELinux context (VAST fix) — add SELinux context to mount options
6. Bulk parallelism defaults — configurable SSH/iDRAC parallelism settings
7. Bulk /etc/hosts update — replace serial loop with bulk_update_hosts module
8. Bulk iDRAC discovery — replace serial loops with bulk_discover_node_specs module
9. Delete obsolete serial tasks — remove read_node_idrac.yml, read_node_idrac_group.yml, update_hosts_munge.yml
10. Single-pass sed for /etc/hosts cleanup — more robust sed command
11. Munge key restart warnings — debug warnings when munge key changes
12. Apptainer tmpdir/pipefail — add pipefail and configurable TMP_DIR
13. Container-mount safe /etc/hosts — atomic heredoc rewrite for overlay mounts

Status File Contracts

• discovery_status.yml: overall_status (success/failed) + bmc_pxe_mapping_file (timestamped path)
• orchestrator_status.yml: overall_status + per-node details
  • PXE boot path: status derived from phone-home verification
  • Provisioning path: status derived from SMD registration

Test plan

• Run discovery playbook and verify discovery_status.yml format
• Run orchestrator with PXE boot and verify orchestrator_status.yml node status
• Run orchestrator without PXE boot and verify orchestrator_status.yml SMD-based status