feat(core+backend/X11): 区分窗口销毁和撤销

src/core/plan.h

@@ -10,6 +10,7 @@ typedef enum effect_type_t {
   ZDWM_EFFECT_UNMAP_WINDOW,
   ZDWM_EFFECT_FOCUS_WINDOW,
   ZDWM_EFFECT_KILL_WINDOW,
+  ZDWM_EFFECT_WITHDRAW_WINDOW,
   ZDWM_EFFECT_MOVE_WINDOW,
   ZDWM_EFFECT_RESIZE_WINDOW,
   ZDWM_EFFECT_CHANGE_BORDER_COLOR,
@@ -61,6 +62,7 @@ typedef struct effect_t {
     effect_only_window_id_t unmap;
     effect_only_window_id_t focus;
     effect_only_window_id_t kill;
+    effect_only_window_id_t withdraw;
     effect_move_window_t move;
     effect_resize_window_t resize;
     effect_change_border_color_t change_border_color;