wl_backend: fix prop_get_wm_class return value (0=fail, 1=success) — broke session save

ROADMAP.md

@@ -34,8 +34,12 @@ positions are tracked in `WWindow` (backend-neutral). The only concern is
 matching restored sessions to native XDG clients via `app_id` instead of
 `WM_CLASS`.
 
+- [x] Save/restore state for Wayland native clients: `PropGetWMClass` already
+  returns the XDG `app_id` on Wayland. Session save no longer bails when
+  `GetCommandForWindow` returns NULL (external Wayland clients have no ICCCM
+  command). Restore matches by `app_id` via instance+class without requiring
+  a command.
 - [ ] Test: save session, restart compositor, verify window positions restored
-- [ ] Add `app_id` to session file alongside `WM_CLASS` for native XDG clients
 - [ ] Verify dock state persistence (icon layout in `~/GNUstep/Defaults/`)
 
 ### 1.2 Multi-Monitor

src/backend/wayland/wl_backend.c

@@ -7067,14 +7067,14 @@ wl_prop_get_wm_class(WNativeWindow win,
     if (v && v->xw_surface) {
         *wm_class    = strdup(v->xw_surface->class    ? v->xw_surface->class    : "x11-client");
         *wm_instance = strdup(v->xw_surface->instance ? v->xw_surface->instance : "x11-client");
-        return 0;
+        return 1;
     }
     const char *app_id = (v && v->xdg_surface && v->xdg_surface->toplevel &&
                           v->xdg_surface->toplevel->app_id)
                          ? v->xdg_surface->toplevel->app_id : "wayland-client";
     *wm_class    = strdup(app_id);
     *wm_instance = strdup(app_id);
-    return 0;
+    return 1;
 }
 
 static Bool