fix: CAT PTT not working for DVK

app.go

@@ -5844,8 +5844,20 @@ func (a *App) TestPTT(cfg AudioSettings) error {
 	if err := a.pttKey(cfg); err != nil {
 		return err
 	}
+	// Hold long enough to be observable. OmniRig is async and coalesces rapid
+	// writes to the same parameter: it stores the desired Tx value and flushes
+	// on its own poll timer, so a key (PM_TX) followed too quickly by an unkey
+	// (PM_RX) can land in ONE flush cycle — OmniRig then sends only the last
+	// value (PM_RX) and the rig never actually transmits (while an already-MOX'd
+	// rig gets dropped by that lone PM_RX). A longer hold guarantees the key
+	// command is sent and held before the release. Serial RTS/DTR is instant,
+	// so it keeps the short window.
+	hold := 600 * time.Millisecond
+	if cfg.PTTMethod == "cat" {
+		hold = 1500 * time.Millisecond
+	}
 	gen := a.pttGenNow()
-	go func() { time.Sleep(600 * time.Millisecond); a.unkeyIfCurrent(gen) }()
+	go func() { time.Sleep(hold); a.unkeyIfCurrent(gen) }()
 	return nil
 }