重构UI架构：分离数据模型和显示逻辑

- 新增 Core 模块：GameObject、LogEntry、AssetItem 数据模型
- 新增 Managers 模块：SceneManager、LogSystem、ProjectManager
- Panel 层只负责显示，不再持有数据
- 解耦 HierarchyPanel 和 InspectorPanel 之间的直接依赖

ui/src/panels/ProjectPanel.cpp

@@ -1,22 +1,13 @@
 #include "ProjectPanel.h"
+#include "Managers/ProjectManager.h"
+#include "Core/AssetItem.h"
 #include <imgui.h>
 #include <imgui_internal.h>
 
 namespace UI {
 
 ProjectPanel::ProjectPanel() : Panel("Project") {
-    m_folders = {"Assets", "Scenes", "Scripts", "Materials", "Prefabs"};
-    
-    m_items = {
-        {"Cube", "Prefab", false},
-        {"Sphere", "Prefab", false},
-        {"Player", "Prefab", false},
-        {"MainScript", "Script", false},
-        {"DefaultMat", "Material", false},
-        {"Scene1", "Scene", false},
-        {"Textures", "Folder", true},
-        {"Models", "Folder", true},
-    };
+    ProjectManager::Get().CreateDemoAssets();
 }
 
 void ProjectPanel::Render() {
@@ -37,11 +28,12 @@ void ProjectPanel::Render() {
     int columns = (int)(panelWidth / (buttonWidth + padding));
     if (columns < 1) columns = 1;
     
-    for (int i = 0; i < m_items.size(); i++) {
+    auto& items = ProjectManager::Get().GetItems();
+    for (int i = 0; i < items.size(); i++) {
         if (i > 0 && i % columns != 0) {
             ImGui::SameLine();
         }
-        RenderAssetItem(m_items[i], i);
+        RenderAssetItem(items[i], i);
     }
     
     ImGui::EndChild();
@@ -51,14 +43,14 @@ void ProjectPanel::Render() {
 void ProjectPanel::RenderAssetItem(const AssetItem& item, int index) {
     ImGui::PushID(index);
     
-    bool isSelected = (m_selectedIndex == index);
+    bool isSelected = (ProjectManager::Get().GetSelectedIndex() == index);
     if (isSelected) {
-        ImGui::PushStyleColor(ImGuiCol_Button, ImVec4(0.26f, 0.59f, 0.98f, 0.40f));
+        ImGui::PushStyleColor(ImGuiCol_Button, ImVec4(0.40f, 0.40f, 0.40f, 0.50f));
     }
     
     ImVec2 buttonSize(80.0f, 90.0f);
     if (ImGui::Button("##Asset", buttonSize)) {
-        m_selectedIndex = index;
+        ProjectManager::Get().SetSelectedIndex(index);
     }
     
     if (isSelected) {