Have CAD be a separate toggle (set cad on/off)

examples/companion_radio/MyMesh.cpp

@@ -259,7 +259,10 @@ float MyMesh::getAirtimeBudgetFactor() const {
 }
 
 int MyMesh::getInterferenceThreshold() const {
-  return 1; // non-zero enables hardware CAD (Channel Activity Detection) before TX
+  return 0; // disabled for now, until currentRSSI() problem is resolved
+}
+bool MyMesh::getCADEnabled() const {
+  return true; // hardware CAD before TX (no CLI toggle on companion; enabled by default)
 }
 
 int MyMesh::calcRxDelay(float score, uint32_t air_time) const {