fix(desktop): stop the Windows serve watchdog from killing healthy backends (salvage #83556)

[teknium1]

Summary

Windows Desktop backends no longer kill themselves at boot: the serve parent-death watchdog now probes the recorded Desktop PID for liveness instead of comparing it to os.getppid().

Root cause: #83406's watchdog assumed HERMES_PARENT_PID (the Electron PID) is the backend's immediate parent. On Windows the Desktop launches the backend through the venv hermes.EXE shim, so the backend's PPID is the shim — the comparison always fails and the watchdog os._exit(0)s a healthy backend ~2s after HERMES_BACKEND_READY. Every Windows Desktop boot on current main hits this; Retry/Repair can't recover because they reinstall the same code.

Salvaged from #83556 by @insane66613 (authorship preserved). Duplicate #83604 by @LKrystalL arrived ~1h later with a weaker Windows-only ctypes probe (access-denied reads a live parent as dead) and no tests.

Changes

• hermes_cli/web_server.py: _is_serve_orphaned() probes the Desktop PID via the Windows-safe gateway.status._pid_exists() (psutil OpenProcess — avoids the os.kill(pid, 0) Ctrl+C trap); probe errors fail safe to "keep serving"; orphan reap intent preserved (dead Desktop still exits 0) on all platforms
• tests/hermes_cli/test_serve_parent_watchdog.py: regression coverage for live owner, dead owner, and broken-probe fail-safe

Validation

Check	Result
test_serve_parent_watchdog (new)	2/2
test_dashboard_admin_endpoints + test_spawn_gateway_restart_reap	pass
E2E: real child process as owner — live kept, dead detected	pass
Attribution audit (audit_pr_attribution.py --fix)	clean

Infographic

[github-actions]

૮ >ﻌ< ა ci review

_{ran on 564fc9e — chore: contributor email mapping for salvaged commit}

⚠️ Warnings

OSV vulnerability scan · View job

2 known vulnerabilities found in pinned dependencies.

• CVE-2026-70608 in package-lock.json
• CVE-2026-70606 in package-lock.json

How to fix:

Review the findings in the Security tab. Update the affected dependencies if a patched version is available.

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debug info

CI timings

CI timings · View report · View job

Wall time 3m14s vs 6m45s (-52.1%). 15 job(s) slower, 9 faster, 1 unchanged.

• Python tests / Run tests slice 10/12: +40.0s
• Python tests / Run tests slice 12/12: +29.0s
• Python tests / Run tests slice 6/12: -11.0s
• Python tests / Run tests slice 3/12: +11.0s
• OS-specific tests / macOS-only tests: +11.0s