Un-parks the rewire that was blocked behind the Ardour double-launch (log 041).
The patch saved with that log no longer applied — perf-tray.py moved under it in
90afa239 — so this is reimplemented against the current file rather than forced;
`git apply --reject` had left the file half-patched and was reset before starting.

PLN, 2026-09-05: "click launch gig started pulsar, not ardour??", then "is our
launch gig now autodoing?".

The old button opened Pulsar and nothing else. That was deliberate — #116 says
the hot path must not be able to start the sound by accident — but the name
promised a gig, so it read as broken rather than as careful, and the rig's real
launcher (the Bridge's RIG UP, which converges every unit and then opens the
apps) had not been pressed in 6.7 days. A safety rule that makes the safe path
invisible protects nothing; it just moves the launch to a hand-typed command.

So the tray and the Bridge now drive the SAME reconciler, and #116 is honoured
by ARMING instead of by crippling — the idiom already proven two menu entries
below on Restart SuperDirt:

- SuperDirt already up  → the press only converges and focuses. One click.
- SuperDirt down        → the press would start the sound. First click arms and
                          says so in a tray notification; a second click, which
                          means reopening the menu, commits. Arming lapses after
                          10 s.
- No confirmation dialog, ever: a modal stealing focus mid-set is its own
  hazard (#136).

"Would this start the sound?" is answered from SuperDirt's unit state, not by
asking the Bridge — the cheap local truth, and it keeps an HTTP round trip out
of the front of a button press. The label carries all three states so the
dangerous one announces itself before it is pressed.

The POST runs in a worker thread and is never waited on. A cold converge takes
~100 s, and the reason PLN launched Ardour by hand mid-evening — believing RIG UP
had failed — was a face that showed a spinner and no window. The Bridge answers
immediately and runs the job in the background; the Bridge page opens right away.
Nothing in the worker touches Qt.

Verified end-to-end, with Ardour already running and SuperDirt up:
  POST /api/rig {"launch_apps":true} → {"ok":true,"status":"started"}
  journal:  pulsar: SPAWNED pid 2779892 (it was down)
            ardour: running → focus
            midimon: running → focus
  ArdourGUI process count: 1 before, 1 after.

That "ardour: running → focus" is the line this whole thread existed to produce:
the last time this path ran it said "launched" while Ardour was up, and the two
instances killed each other over the session lock.

Tray after restart: active, NRestarts=0. Incidentally closes the suspected
perf-tray memory leak — systemd's own accounting reports a 59.6M memory peak
over 2h15m wall clock, so the "2.6 GB RSS" in the hand-off was a misread of
virtual size, not a leak. Nothing to fix.