Handle WindowManager.getCurrent() safely on Linux Wayland

[Copilot]

On Linux Wayland/XWayland sessions, calling WindowManager.getCurrent() can hit a GTK/GDK assertion path (gdk_device_get_window_at_position_double) and emit critical errors when resolving the current window.

• Problem summary

  • getCurrent() relied on a native “current focused window” lookup that is not reliable under Wayland session semantics in this environment.

• What changed

  • Added Linux Wayland session detection in WindowManager (WAYLAND_DISPLAY / XDG_SESSION_TYPE=wayland).
  • Updated getCurrent() to use a safe fallback on Wayland:
    • return the first managed window from getAll() (or null if none),
    • skip the native native_window_manager_get_current() call in this path.
  • Kept existing behavior unchanged for non-Linux or non-Wayland sessions.

• Resulting behavior

  • Avoids the problematic native focus-query path on Linux Wayland while preserving API shape (Window?) and existing behavior elsewhere.

final windowManager = WindowManager.instance;
final window = windowManager.getCurrent(); // Wayland: resolved via managed-window fallback