Properly persist bluetooth mode changes

src/audio/audio_fsm.cpp

@@ -113,7 +113,6 @@ void AudioState::react(const SetVolumeBalance& ev) {
 }
 
 void AudioState::react(const OutputModeChanged& ev) {
-  // TODO: handle SetInUse
   ESP_LOGI(kTag, "output mode changed");
   auto new_mode = sServices->nvs().OutputMode();
   sOutput->SetMode(IAudioOutput::Modes::kOff);

src/ui/ui_fsm.cpp

@@ -85,11 +85,16 @@ lua::Property UiState::sBluetoothEnabled{
     if (std::get<bool>(val)) {
       sServices->bluetooth().Enable();
       sServices->bluetooth().SetDeviceDiscovery(true);
+      sServices->nvs().OutputMode(drivers::NvsStorage::Output::kBluetooth);
     } else {
       sServices->bluetooth().Disable();
+      sServices->nvs().OutputMode(drivers::NvsStorage::Output::kHeadphones);
     }
+    events::Audio().Dispatch(audio::OutputModeChanged{});
     return true;
-    }};
+  }
+};
+
 lua::Property UiState::sBluetoothConnected{false};
 lua::Property UiState::sBluetoothPairedDevice{
     std::monostate{}, [](const lua::LuaValue& val) {