Minutes after test-sc-watchdog exited, PLN got a STICKY desktop notification:

    "3 restarts in 10 min. Giving up — this needs your eyes.
     journalctl --user -u scwd-test-1269280.service -n 50"

scwd-test-1269280.service was the test's own FAKE transient unit. By the time the
notification was read, it had been torn down — so the suggested command returns
nothing, about a failure that never happened, while the real rig was playing fine.

Two defects in one message. The test could reach a real notification daemon at all;
and the give-up path is deliberately urgency=critical/sticky, which is correct for a
real outage and actively harmful for a fake one — it cannot be dismissed by waiting.

Fix: SCWD_NO_NOTIFY=1, honoured by notify() and set by the harness. A test must never
be able to page a human about something that is not real.

Re-run green: 7 passed, 0 failed, and silent. The log still shows the rate limiter
walking (0 prior) -> (1 prior) -> (2 prior) -> GIVING UP, so suppressing the toast
did not suppress the evidence — the assertion reads the log, not the notification.

Same family as the flap it was written to catch: a supervisory tool whose side
effects escape the scope it was reasoning about.