Add XCUI input state validation sandbox batch

new_editor/src/Application.h

@@ -41,6 +41,8 @@ private:
     void Shutdown();
     void RenderFrame();
     void OnResize(UINT width, UINT height);
+    void QueuePointerEvent(::XCEngine::UI::UIInputEventType type, ::XCEngine::UI::UIPointerButton button, WPARAM wParam, LPARAM lParam);
+    void QueuePointerLeaveEvent();
     void QueuePointerWheelEvent(short wheelDelta, WPARAM wParam, LPARAM lParam);
     bool LoadStructuredScreen(const char* triggerReason);
     void RefreshStructuredScreen();
@@ -63,6 +65,7 @@ private:
     std::chrono::steady_clock::time_point m_lastReloadPollTime = {};
     std::uint64_t m_frameIndex = 0;
     std::vector<::XCEngine::UI::UIInputEvent> m_pendingInputEvents = {};
+    bool m_trackingMouseLeave = false;
     bool m_useStructuredScreen = false;
     std::string m_runtimeStatus = {};
     std::string m_runtimeError = {};