[codex] Harden ORION gateway guard and add machine digest

[cmsjade5000]

Summary

• harden the ORION gateway resurrector so healthy /readyz or /healthz probes prevent unnecessary restarts when gateway status JSON fails
• add a read-only machine/ORION digest command and make target
• document the digest and cover false-failure regressions with tests

Validation

• python3 -m unittest tests/test_resurrect_orion_mac.py tests/test_orion_machine_status.py
• bash -n scripts/resurrect_orion_mac.sh scripts/openclaww.sh scripts/orion_local_maintenance_runner.sh
• git diff --check
• make machine-status
• python3 -m unittest discover -s tests -p 'test_*.py'

Notes

This is a stacked PR based on codex/orion-codex-0128-follow-through because the resurrector/test files are not on main yet. It performs no LaunchAgent install, repair, restart, provider probe, or Telegram send.