add notifications

src/app.cpp

@@ -1,13 +1,14 @@
 #include "app.hpp"
 
-#include <exception>
-#include <iostream>
 #include <sigc++/sigc++.h>
+#include <vector>
+#include "services/notification.hpp"
 
 App::App() {
     this->app = Gtk::Application::create("org.example.mybar");
     this->setupServices();
     this->hyprlandService = HyprlandService::getInstance();
+    this->notificationService = std::make_shared<NotificationService>();
 
     app->signal_activate().connect([&]() {
         auto display  = Gdk::Display::get_default();
@@ -17,7 +18,7 @@ App::App() {
             auto monitor = std::dynamic_pointer_cast<Gdk::Monitor>(
                 monitors->get_object(i)
             );
-            
+
             if (monitor) {
                 auto bar = std::make_shared<Bar>(monitor->gobj());