fix: window position/size persistence under Wayland (v1.3.2)

linux/runner/my_application.cc

@@ -150,6 +150,14 @@ static void my_application_class_init(MyApplicationClass* klass) {
 static void my_application_init(MyApplication* self) {}
 
 MyApplication* my_application_new() {
+  // GTK3 ignores gtk_window_move under Wayland (window opens centered).
+  // Force X11 backend when an X server is available (XWayland) so window
+  // position/size persistence works.
+  if (g_getenv("WAYLAND_DISPLAY") != nullptr &&
+      g_getenv("DISPLAY") != nullptr) {
+    g_setenv("GDK_BACKEND", "x11", FALSE);
+  }
+
   // Set the program name to the application ID, which helps various systems
   // like GTK and desktop environments map this running application to its
   // corresponding .desktop file. This ensures better integration by allowing