What does this PR do?

This PR fixes a Windows-specific gateway startup failure caused by PID liveness probing.

Hermes uses os.kill(pid, 0) to check whether a PID recorded in the gateway PID file is still alive. That works in most cases, but on Windows some stale or invalid PIDs can raise a plain OSError such as WinError 11 instead of the expected ProcessLookupError or PermissionError. Because that case was not handled, gateway startup could crash while checking for an existing process instead of safely treating the PID record as stale.

This fix centralizes PID liveness probing in a helper and treats Windows-specific OSError probe failures as “not alive”. That keeps startup resilient and prevents stale PID files from crashing the gateway.

Related Issue

Fixes #

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

• Updated gateway/status.py to add _pid_looks_alive(pid) for centralized PID liveness checks.
• Changed gateway PID validation to treat Windows OSError probe failures as stale/non-running PIDs instead of crashing.
• Reused the new helper in both get_running_pid() and scoped lock liveness checks.
• Added a regression test in tests/gateway/test_status.py covering the Windows OSError PID probe case.

How to Test

1. Run python -m pytest tests/gateway/test_status.py -q
2. Confirm the new Windows regression test passes along with the existing gateway status tests.
3. Reproduce the original scenario on Windows with a stale gateway.pid and verify Hermes no longer crashes during startup PID detection.

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: Windows 11

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — or N/A
• I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A
• I've updated tool descriptions/schemas if I changed tool behavior — or N/A

Screenshots / Logs

Test run:

python -m pytest tests/gateway/test_status.py -q
...............                                                          [100%]
15 passed in 6.98s