fix: linux taskbar ikonu (gtk default icon + hicolor tema indeksi + StartupWMClass), windows .ico yenilendi, .deb guncellendi

linux/runner/my_application.cc

@@ -156,6 +156,20 @@ MyApplication* my_application_new() {
   // the application to be recognized beyond its binary name.
   g_set_prgname(APPLICATION_ID);
 
+  // App-level default icon. GTK writes _NET_WM_ICON from this when windows
+  // are realized, so taskbars show the application icon.
+  g_autofree gchar* exe_path = g_file_read_link("/proc/self/exe", nullptr);
+  if (exe_path != nullptr) {
+    g_autofree gchar* bundle_dir = g_path_get_dirname(exe_path);
+    g_autofree gchar* icon_path =
+        g_build_filename(bundle_dir, "data", "imajviewer.png", nullptr);
+    GdkPixbuf* pixbuf = gdk_pixbuf_new_from_file(icon_path, nullptr);
+    if (pixbuf != nullptr) {
+      gtk_window_set_default_icon(pixbuf);
+      g_object_unref(pixbuf);
+    }
+  }
+
   return MY_APPLICATION(g_object_new(my_application_get_type(),
                                      "application-id", APPLICATION_ID, "flags",
                                      G_APPLICATION_NON_UNIQUE, nullptr));