ownerAlive() treated EPERM (permission denied) the same as ESRCH
(process not found), causing the server to self-terminate within 60s
whenever the owner process ran as a different user. This affected WSL
(owner is a Windows process), Tailscale SSH, and any cross-user
scenario.
The fix: `return e.code === 'EPERM'` — if we get permission denied,
the process is alive; we just can't signal it.
Tested on Linux via Tailscale SSH with a root-owned grandparent PID:
- Server survives past the 60s lifecycle check (EPERM = alive)
- Server still shuts down when owner genuinely dies (ESRCH = dead)
Fixes#879
The session directory now contains two peers: content/ (HTML served to
the browser) and state/ (events, server-info, pid, log). Previously
all files shared a single directory, making server state and user
interaction data accessible over the /files/ HTTP route.
Also fixes stale test assertion ("Waiting for Claude" → "Waiting for
the agent").
Reported-By: 吉田仁
Metadata files (.server-info, .events, .server.pid, .server.log,
.server-stopped) were stored in the same directory served over HTTP,
making them accessible via the /files/ route. They now live in a .meta/
subdirectory that is not web-accessible.
Also fixes a stale test assertion ("Waiting for Claude" → "Waiting for
the agent").
Reported-By: 吉田仁
