feat: impl lifecycle with tests

src/engine/core/engine.cpp

@@ -132,12 +132,12 @@ MscEngine::getLoadedModules() const
   return result;
 }
 
-MscEngineModule &MscEngine::getModule(const std::string &name)
+std::shared_ptr<MscEngineModule> &MscEngine::getModule(const std::string &name)
 {
   for (auto &module : _modules)
   {
     if (module.get()->getName() == name)
-      return *module.get();
+      return module;
   }
 
   throw std::runtime_error("Module not found: " + name);
@@ -153,3 +153,8 @@ MscEngine::createDBProvider(const std::string &filepath)
 {
   return std::make_unique<MscEngineDBProvider>(filepath);
 }
+
+void MscEngine::requestStop()
+{
+  this->stop(); // TODO: заменить на флаг
+}