Key changes in wl_backend.c:
- wl_atom_intern: call XInternAtom on XWayland display (was returning 0)
- Add wl_or_view struct to track override_redirect XWayland surfaces
- handle_xwayland_new_surface: composite OR surfaces via scene graph
- frame_create_toplevel/child: create real X11 windows on XWayland
- frame_destroy/configure: delegate to Xlib
- window_map/unmap/move/resize: fall through to Xlib for frame windows
- stacking_raise/lower: update scene graph + Xlib fallback
- event_flush/sync: call XFlush/XSync on XWayland display
- window_set_border/border_width/clear: delegate to Xlib
- window_get_rect: query XWayland geometry for non-toplevel windows
Note: frame creation via XWayland is a temporary bridge. The correct
architectural approach is native scene-buffer rendering with pixman.