`sunbeam connect` now fork-execs itself with a hidden `__vpn-daemon`
subcommand instead of running the daemon in-process. The user-facing
command spawns the child detached (stdio → log file, setsid for no
controlling TTY), polls the IPC socket until the daemon reaches
Running, prints a one-line status, and exits. The user gets back to
their shell immediately.
- src/cli.rs: `Connect { foreground }` instead of unit. Add hidden
`__vpn-daemon` Verb that the spawned child runs.
- src/vpn_cmds.rs: split into spawn_background_daemon (default path)
and run_daemon_foreground (used by both `connect --foreground` and
`__vpn-daemon`). Detached child uses pre_exec(setsid) and inherits
--context from the parent so it resolves the same VPN config.
Refuses to start if a daemon is already running on the control
socket; cleans up stale socket files. Switches the proxy bind from
16443 (sienna's existing SSH tunnel uses it) to 16579.
- sunbeam-net/src/daemon/lifecycle: add a SocketGuard RAII type so the
IPC control socket is unlinked when the daemon exits, regardless of
shutdown path. Otherwise `vpn status` after a clean disconnect would
see a stale socket and report an error.
End-to-end smoke test against the docker stack:
$ sunbeam connect
==> VPN daemon spawned (pid 90072, ...)
Connected (100.64.0.154, fd7a:115c:a1e0::9a) — 2 peers visible
$ sunbeam vpn status
VPN: running
addresses: 100.64.0.154, fd7a:115c:a1e0::9a
peers: 2
derp home: region 0
$ sunbeam disconnect
==> Asking VPN daemon to stop...
Daemon acknowledged shutdown.
$ sunbeam vpn status
VPN: not running
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