a9da65e put the raise inside the serve script, which runs as `User=dank`: the
knob is root-owned 0644, so `-w` is false and the write silently failed — the
gate printed its refusal on a cap it had just failed to move. The privileged
path is systemd's `+` prefix: `ExecStartPre=+scripts/ttm-preflight.sh --raise`
runs as root even under `User=`, before ExecStart, so `Restart=always` can
never outrun it. The lib is now also executable (`--raise` sources the env file
and verifies), and keeps a `sudo -n` fallback for a human running the gate from
a shell.
Seam: the refusal cases run with a PATH that has `cat`+`bash` and NO `sudo`
(root writes a 444 file, so a passwordless dev box would have tested nothing),
and both now assert the gate's own exit 1, not merely non-zero. New seam covers
the unit line and the `--raise` entry point end to end (writable knob -> raised,
no args -> usage exit 2).