core: 添加 pointer enter 事件

docs/min_core_draft/wm_event.h

@@ -16,6 +16,8 @@ typedef enum wm_event_type_t {
   WM_EVENT_POINTER_BUTTON_PRESS,
   WM_EVENT_POINTER_BUTTON_RELEASE,
   WM_EVENT_POINTER_MOTION,
+  // 指针焦点进入某个窗口；对应 X11 EnterNotify / Wayland wl_pointer.enter
+  WM_EVENT_POINTER_ENTER,
   WM_EVENT_WINDOW_MAP_REQUEST,
   WM_EVENT_WINDOW_REMOVE,
   WM_EVENT_WINDOW_METADATA_CHANGED,
@@ -64,6 +66,15 @@ typedef struct wm_pointer_motion_event_t {
   wm_window_id_t window;
 } wm_pointer_motion_event_t;
 
+typedef struct wm_pointer_enter_event_t {
+  // 全局桌面坐标
+  wm_point_t root;
+  // 相对 window 的坐标；若 window == WM_WINDOW_ID_INVALID，则该值未定义
+  wm_point_t local;
+  // 当前进入并获得 pointer focus 的窗口；若未命中窗口，则为 WM_WINDOW_ID_INVALID
+  wm_window_id_t window;
+} wm_pointer_enter_event_t;
+
 typedef struct wm_window_map_request_event_t {
   wm_window_info_t info;
   // 仅用于 manage 路由判断，不进入持久 state
@@ -204,6 +215,7 @@ typedef struct wm_event_t {
     wm_pointer_button_event_t pointer_button_press;
     wm_pointer_button_event_t pointer_button_release;
     wm_pointer_motion_event_t pointer_motion;
+    wm_pointer_enter_event_t pointer_enter;
     wm_window_map_request_event_t window_map_request;
     wm_window_remove_event_t window_remove;
     wm_window_metadata_changed_event_t window_metadata_changed;