fix(tci): TUNE can be switched off again, and the meters watch it

Two faults with one cause: this radio does not echo 'tune:0,true'.

So the panel never knew a tune was running. The button stayed on TUNE and
every further press sent another START — there was no way to stop it from
here at all. The state is recorded when the command is sent now; whatever
the radio says afterwards still wins, it simply never says anything.

And the transmit meters were asked for only while t.tx, which a tune
carrier does not set: the radio reports tuning as its own state, not as a
transmission. So power and SWR sat at zero for the whole tune — the exact
carrier an operator holds a tune for in order to watch an SWR on. They now
follow PTT or TUNE, and the S-meter reads '—' under our own carrier
either way.

internal/cat/tci_panel.go

@@ -341,7 +341,18 @@ func (t *TCI) SetLock(on bool) error { return t.send(fmt.Sprintf("lock:0,%t;", o
 //
 // It TRANSMITS, at tune_drive rather than at drive — which is the setting to
 // check before pressing it, and why the panel shows the two side by side.
-func (t *TCI) SetTune(on bool) error { return t.send(fmt.Sprintf("tune:0,%t;", on)) }
+//
+// The state is recorded HERE rather than waited for. This radio does not echo
+// "tune:0,true", so the panel had no way of knowing a tune was running: the
+// button stayed on TUNE and every further press sent another START, which is
+// why it could not be switched off again. Whatever the radio says afterwards
+// still wins — it simply never says anything.
+func (t *TCI) SetTune(on bool) error {
+	t.mu.Lock()
+	t.panel.st.Tuning = on
+	t.mu.Unlock()
+	return t.send(fmt.Sprintf("tune:0,%t;", on))
+}
 
 func clampTCIPct(v int) int {
 	if v < 0 {