fix: audio volume setting not applied on load

src/engine.cpp

@@ -58,7 +58,7 @@ inline void create_channel(Engine* engine, std::string name, NumberSetting& sett
     }
     engine->keepAlive(setting.observe([=](auto value) {
         audio::get_channel(name)->setVolume(value*value);
-    }));
+    }, true));
 }
 
 Engine::Engine(EngineSettings& settings, SettingsHandler& settingsHandler, EnginePaths* paths)