refactor: 解耦重构——还清四处架构债（对齐 UE/Unity 分层）

- SceneRenderer：场景→渲染数据翻译层（UE FSceneRenderer / Unity CullingResults
  模式），收口相机/灯光/光空间矩阵/双视图剔除，Renderer 只编排
- pass 对象化（Unity ScriptableRenderPass 模式）：8 个 pass lambda 拆为
  Passes::{Shadow,Forward,Bloom,Tonemap,ImGui,Present}，BuildGraph 超级函数消失；
  SceneGpu/FullscreenGpu 承接共享装配
- 中性 AssetRef（Core 层）：ECS 组件不再依赖 Assets 模块（Unity InstanceID 思路）
- IAssetUploader 接口：AssetManager 不感知 Vulkan 具体类，上传服务由渲染层
  VulkanAssetUploader 提供
- Renderer 公共 API 不变（App 层零改动），编译零错误 validation 零警告

Engine/src/Assets/AssetManager.cpp

@@ -3,41 +3,31 @@
 //
 
 #include <Engine/Assets/AssetManager.h>
-#include <Engine/Vulkan/Device.h>
-#include <Engine/Vulkan/MemoryAllocator.h>
-#include <Engine/Vulkan/DescriptorManager.h>
 #include <Engine/Core/Log.h>
 
 namespace Engine::Assets {
 
-    AssetManager::AssetManager(Device& device, MemoryAllocator& allocator,
-                               DescriptorManager& descriptors,
-                               vk::DescriptorSetLayout textureLayout)
-        : m_Device(device), m_Allocator(allocator),
-          m_Descriptors(descriptors), m_TextureLayout(textureLayout)
+    AssetManager::AssetManager(IAssetUploader& uploader)
+        : m_Uploader(uploader)
     {
         ENGINE_INFO("AssetManager created");
     }
 
-    ModelHandle AssetManager::LoadModel(const std::string& path)
+    ModelRef AssetManager::LoadModel(const std::string& path)
     {
-        return m_Models.Load(path, [this](const std::string& p) -> Scope<Model> {
-            // GPU 上传在此发生：资产层调用渲染层接口完成 buffer/image 创建
-            return CreateScope<Model>(
-                m_Device, m_Allocator, m_Descriptors, m_TextureLayout, p);
-        });
+        // GPU 上传经接口发生在渲染层实现里，本层只管缓存与句柄
+        return m_Models.Load(path,
+            [this](const std::string& p) { return m_Uploader.LoadModel(p); });
     }
 
-    ModelHandle AssetManager::CreatePlane(f32 halfSize, u8 r, u8 g, u8 b)
+    ModelRef AssetManager::CreatePlane(f32 halfSize, u8 r, u8 g, u8 b)
     {
         // 程序化资产复用同一缓存：键 = 伪路径 + 参数
         std::string key = "procedural://plane/" + std::to_string(halfSize) +
                           "/" + std::to_string(r) + "," + std::to_string(g) +
                           "," + std::to_string(b);
-        return m_Models.Load(key, [&](const std::string&) -> Scope<Model> {
-            return Model::CreatePlane(m_Device, m_Allocator, m_Descriptors,
-                                      m_TextureLayout, halfSize, r, g, b);
-        });
+        return m_Models.Load(key,
+            [&](const std::string&) { return m_Uploader.CreatePlane(halfSize, r, g, b); });
     }
 
 } // namespace Engine::Assets