Two bugs caused the brainstorm server to self-terminate within 60s:
1. ownerAlive() treated EPERM (permission denied) as "process dead".
When the owner PID belongs to a different user (Tailscale SSH,
system daemons), process.kill(pid, 0) throws EPERM — but the
process IS alive. Fixed: return e.code === 'EPERM'.
2. On WSL, the grandparent PID resolves to a short-lived subprocess
that exits before the first 60s lifecycle check. The PID is
genuinely dead (ESRCH), so the EPERM fix alone doesn't help.
Fixed: validate the owner PID at server startup — if it's already
dead, it was a bad resolution, so disable monitoring and rely on
the 30-minute idle timeout.
This also removes the Windows/MSYS2-specific OWNER_PID="" carve-out
from start-server.sh, since the server now handles invalid PIDs
generically at startup regardless of platform.
Tested on Linux (magic-kingdom) via Tailscale SSH:
- Root-owned owner PID (EPERM): server survives ✓
- Dead owner PID at startup (WSL sim): monitoring disabled, survives ✓
- Valid owner that dies: server shuts down within 60s ✓
Fixes#879
9f04f06351