fix: CAT PTT not working for DVK

internal/cat/omnirig.go

@@ -414,6 +414,16 @@ func (o *OmniRig) SetPTT(on bool) error {
 		debugLog.Printf("OmniRig.SetPTT error: %v", err)
 		return fmt.Errorf("set Tx=%s: %w", name, err)
 	}
+	// Read the Tx param straight back. OmniRig is async — this may still show the
+	// previous value for a poll cycle — but if a key/unkey NEVER changes it, the
+	// write was coalesced or the rig isn't honouring PM_TX/PM_RX (wrong .ini).
+	if v, err := oleutil.GetProperty(o.rig, "Tx"); err == nil {
+		txState := "PM_RX"
+		if v.Val&pmTX != 0 {
+			txState = "PM_TX"
+		}
+		debugLog.Printf("OmniRig.SetPTT: Tx readback = 0x%X (%s)", v.Val, txState)
+	}
 	return nil
 }