Implements the update/restart action buttons called out in issue #961:
- Backend (web_server.py): two new POST endpoints
- /api/actions/restart-gateway — sends SIGUSR1 to the running gateway PID
- /api/actions/update-hermes — runs `hermes update --yes` in a subprocess
- Frontend (api.ts): restartGateway() / updateHermes() API helpers + ActionResponse type
- UI (StatusPage.tsx): "Actions" card with Restart Gateway and Update Hermes buttons
- idle → running (spinner) → success/failure states
- feedback detail text; auto-resets to idle after 8 s
- i18n: new status.actions / restartGateway / updateHermes strings in en, zh, and types
Refs #961
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>