重构ui_editor：向引擎核心类型对齐

- 删除UI::Event，使用XCEngine::Core::Event替代
- GameObject.h重构，Component添加friend class Entity
- LogEntry使用XCEngine::Debug::LogLevel
- SceneManager/SelectionManager使用XCEngine::Core::Event
- LogSystem使用XCEngine::Debug::LogLevel
- CMakeLists.txt添加engine/include路径

ui_editor/src/Managers/LogSystem.h

@@ -10,7 +10,7 @@ class LogSystem {
 public:
     static LogSystem& Get();
     
-    void AddLog(LogEntry::Level level, const std::string& message);
+    void AddLog(XCEngine::Debug::LogLevel level, const std::string& message);
     void Clear();
     const std::vector<LogEntry>& GetLogs() const { return m_logs; }
     
@@ -23,4 +23,4 @@ private:
     std::function<void()> m_callback;
 };
 
-}
+}