Fix gateway status detection inside Docker containers

[gnanirahulnutakki]

Summary

• fall back to a portable ps ax -o pid=,command= scan when ps -A eww is unavailable
• treat the gateway PID file as a status fallback before reporting that the manual gateway is down
• cover the fallback ps path and PID-file status path with regression tests

Fixes #10761

Testing

• pytest -q tests/hermes_cli/test_update_gateway_restart.py -k "FindGatewayPidsExclude or falls_back_to_portable_ps"
• pytest -q tests/hermes_cli/test_gateway_service.py -k "pid_file_when_process_scan_misses or termux_shows_manual_guidance"

[teknium1]

Closing as superseded by #22860.

Triage notes (medium confidence):
main already integrates gateway.status.get_running_pid into find_gateway_pids (hermes_cli/gateway.py:527-529) and gateway_command status path; PR #22860 'detect gateway process via /proc in Docker without procps' addresses the Docker detection case

Thanks for the contribution — the underlying problem this PR addresses has been resolved by the linked PR on current main. If you believe this was closed in error, please comment and we'll reopen.

(Bulk-closed during a CLI PR triage sweep.)