feat: RenderGraph 帧历史资源（ReadHistory）+ TemporalDiff 验证 pass

- PassBuilder::ReadHistory：读上一帧槽位 ((slot-1+F) mod F) 的物理镜像，
  TAA/运动模糊等时域效果的前置能力，RG 最后一个已知边界补齐
- 历史读不建拓扑边（跨帧依赖由同队列提交序保证）、不入本帧状态链、
  不改生命周期；剔除照常参与（生产者存活判定）
- 历史 barrier：首帧走 first（old=Undefined），之后走 steady 且
  src=ALL_COMMANDS|MEMORY_WRITE 显式闭合跨帧可用性+可见性；
  有历史读的资源，常规 entry steady 的 src 同样升级（历史读打破了
  同槽位 fence 全等保前提）
- TemporalDiff 调试 pass：|上一帧−当前帧|×增益，静止=黑/运动边缘发光
  即链路正确；Tonemap binding2 经 push 开关切调试视图
- 编译零错误、validation 零警告、8 秒冒烟通过（9 pass 全活跃）

Engine/src/Renderer/Renderer.cpp

@@ -16,6 +16,7 @@
 #include <Engine/Renderer/Passes/ForwardPass.h>
 #include <Engine/Renderer/Passes/BloomPass.h>
 #include <Engine/Renderer/Passes/TonemapPass.h>
+#include <Engine/Renderer/Passes/TemporalDiffPass.h>
 #include <Engine/Renderer/Passes/ImGuiPass.h>
 #include <Engine/Renderer/Passes/PresentPass.h>
 #include <Engine/Vulkan/Device.h>
@@ -143,6 +144,8 @@ namespace Engine
     void Renderer::SetBloomThreshold(f32 v) { m_PostParams->bloomThreshold = v; }
     f32 Renderer::GetBloomStrength() const { return m_PostParams->bloomStrength; }
     void Renderer::SetBloomStrength(f32 v) { m_PostParams->bloomStrength = v; }
+    bool Renderer::GetShowTemporalDiff() const { return m_PostParams->showTemporalDiff; }
+    void Renderer::SetShowTemporalDiff(bool b) { m_PostParams->showTemporalDiff = b; }
 
     u32 Renderer::GetMainInstanceCount() const
     {
@@ -194,6 +197,12 @@ namespace Engine
             "BloomB",
             RG::TextureDesc{vk::Format::eR16G16B16A16Sfloat, 0, 0, 0.5f});
 
+        // 帧历史差异（调试视图）：|上一帧 − 当前帧| × 增益。
+        // 帧历史机制（ReadHistory）的验证消费端，也是 TAA 的参考形态
+        m_TemporalDiff = m_RenderGraph->CreateTexture(
+            "TemporalDiff",
+            RG::TextureDesc{vk::Format::eR16G16B16A16Sfloat, 0, 0, 0.5f});
+
         // ---- pass 注册：执行序由拓扑排序决定，与注册顺序无关 ----
         // 要加新 pass：new 一个 RenderPass 子类，在这里 push 一行。
         FrameSceneData& frame = m_SceneRenderer->Frame();
@@ -201,10 +210,13 @@ namespace Engine
             *m_SceneGpu, frame, m_ShadowMap));
         m_Passes.push_back(CreateScope<Passes::ForwardPass>(
             *m_SceneGpu, frame, m_HDRColor, m_Depth, m_ShadowMap));
+        m_Passes.push_back(CreateScope<Passes::TemporalDiffPass>(
+            *m_FullscreenGpu, /*gain*/ 8.0f, m_HDRColor, m_TemporalDiff));
         m_Passes.push_back(CreateScope<Passes::BloomPass>(
             *m_FullscreenGpu, *m_PostParams, m_HDRColor, m_BloomA, m_BloomB));
         m_Passes.push_back(CreateScope<Passes::TonemapPass>(
-            *m_FullscreenGpu, *m_PostParams, m_HDRColor, m_BloomA, m_Backbuffer));
+            *m_FullscreenGpu, *m_PostParams, m_HDRColor, m_BloomA,
+            m_TemporalDiff, m_Backbuffer));
         m_Passes.push_back(CreateScope<Passes::ImGuiPass>(
             &m_ImGuiLayer, m_Backbuffer));
         m_Passes.push_back(CreateScope<Passes::PresentPass>(m_Backbuffer));