Daemon management: Windows cross-platform support

[Aaronontheweb]

Context

Task 1.29 implemented daemon management commands (netclaw daemon start|stop|status|install|uninstall). The current implementation is Linux/macOS-focused:

• Graceful stop uses kill(pid, SIGTERM) via P/Invoke to libc — falls back to Process.Kill() (SIGKILL equivalent) on Windows
• PID file at ~/.netclaw/netclaw.pid — works cross-platform but is not the Windows convention
• Service install/uninstall targets systemd only — prints an error on non-Linux platforms

What needs to change for Windows

Graceful shutdown

• Windows has no SIGTERM. Options:
  • Use GenerateConsoleCtrlEvent (Ctrl+C) if the daemon has a console
  • Use a named event/mutex that the daemon listens for
  • Use the daemon's /api/health/ready endpoint pattern — add a /api/shutdown endpoint

Service registration

• Replace systemd unit generation with Windows Service registration
• Options: sc.exe create, or use Microsoft.Extensions.Hosting.WindowsServices so the daemon can run as both console app and Windows service
• May need a separate install-service flow since Windows services have different lifecycle semantics

PID file

• PID files work but aren't idiomatic on Windows
• Consider using a named mutex for single-instance enforcement on Windows instead

Scope

This is a follow-up to the daemon+thin-client architecture work. Not blocking MVP (Linux homelab target), but needed before any Windows distribution.