新增 Prefab 系统：实体子树存取 + 编辑器 Save As Prefab/拖入实例化 + 脚本 Instantiate

App/editor/panels/AssetBrowserPanel.cpp

@@ -7,6 +7,7 @@
 #include "ControllerEditorPanel.h" // kControllerDragPayload + 双击打开控制器编辑器
 
 #include <Engine/Core/Log.h>
+#include <Engine/Serialization/SceneSerializer.h>
 
 #include <imgui.h>
 
@@ -27,10 +28,12 @@ namespace {
     // 类型过滤（下标即身份）：0 = All
     constexpr const char* kTypeNames[] = {"All",       "Models",
                                           "Textures",  "Scenes",
-                                          "Materials", "Controllers"};
+                                          "Materials", "Controllers",
+                                          "Prefabs"};
 
     // 资产类别：按扩展名分派（过滤用）
-    enum class Kind { Model, Texture, Scene, Material, AnimClip, Other };
+    enum class Kind { Model, Texture, Scene, Material, AnimClip, Prefab,
+                      Other };
 
     Kind KindOf(const std::filesystem::path& p)
     {
@@ -59,6 +62,10 @@ namespace {
         {
             return Kind::AnimClip;
         }
+        if (ext == ".prefab")
+        {
+            return Kind::Prefab;
+        }
         return Kind::Other;
     }
 
@@ -71,6 +78,7 @@ namespace {
             case 3: return kind == Kind::Scene;
             case 4: return kind == Kind::Material;
             case 5: return kind == Kind::AnimClip;
+            case 6: return kind == Kind::Prefab;
             default: return true;
         }
     }
@@ -85,6 +93,7 @@ namespace {
             case Kind::Scene: return "[S]";
             case Kind::Material: return "[Ma]";
             case Kind::AnimClip: return "[An]";
+            case Kind::Prefab: return "[Pf]";
             default: return "[ ]";
         }
     }
@@ -121,7 +130,7 @@ void AssetBrowserPanel::Draw(const EditorContext& ctx)
     }
     ImGui::SameLine();
     ImGui::SetNextItemWidth(110.0f);
-    ImGui::Combo("##type", &m_TypeFilter, kTypeNames, 6);
+    ImGui::Combo("##type", &m_TypeFilter, kTypeNames, 7);
     ImGui::SameLine();
     ImGui::SetNextItemWidth(140.0f);
     ImGui::InputTextWithHint("##name", "filter", m_NameFilter,
@@ -296,6 +305,16 @@ void AssetBrowserPanel::DrawFileList(const EditorContext& ctx,
             ImGui::EndDragDropSource();
         }
 
+        // .prefab 拖拽源：拖到 Outliner（节点=挂其下 / 空白区=挂根）
+        // 实例化整棵子树（kPrefabDragPayload）
+        if (item.kind == Kind::Prefab && ImGui::BeginDragDropSource())
+        {
+            ImGui::SetDragDropPayload(kPrefabDragPayload,
+                                      assetPath.c_str(), assetPath.size() + 1);
+            ImGui::TextUnformatted(name.c_str());
+            ImGui::EndDragDropSource();
+        }
+
         // 双击：.material 打开 Material Editor；.animctrl 打开
         // Controller Editor；model/HDR 进缓存预热（路径去重，重复
         // 双击零成本）；场景加载含环境恢复/选中清理流程，提示走
@@ -328,6 +347,16 @@ void AssetBrowserPanel::DrawFileList(const EditorContext& ctx,
                 ENGINE_INFO("AssetBrowser: load scenes via File menu ({})",
                             assetPath);
             }
+            else if (item.kind == Kind::Prefab && ctx.scene && ctx.assets)
+            {
+                // 双击 = 快捷实例化（授权位姿落点，选中交给 Outliner
+                // 手动改）；拖拽实例化见 Outliner 落点
+                const auto root = Engine::Serialization::SceneSerializer::
+                    InstantiatePrefab(*ctx.scene, *ctx.assets, assetPath);
+                ENGINE_INFO("AssetBrowser: prefab '{}' instantiated "
+                            "(valid={})",
+                            assetPath, root != entt::null);
+            }
         }
 
         // hover 信息卡（UE Content Browser 式）：类型/大小/修改时间/加载状态
@@ -336,11 +365,12 @@ void AssetBrowserPanel::DrawFileList(const EditorContext& ctx,
             ImGui::BeginTooltip();
             ImGui::TextUnformatted(name.c_str());
             ImGui::Separator();
-            // 与 Kind 枚举逐位对齐（Kind::Other = 5）——漏项 = tooltip
+            // 与 Kind 枚举逐位对齐（Kind::Other = 6）——漏项 = tooltip
             // 数组越界读
             static const char* kKindNames[] = {"Model", "Texture/Environment",
                                                "Scene", "Material",
-                                               "Controller", "File"};
+                                               "Controller", "Prefab",
+                                               "File"};
             ImGui::Text("type: %s", kKindNames[static_cast<int>(item.kind)]);
             namespace fs = std::filesystem;
             std::error_code ec;