docs: fix README.md project structure to match actual codebase

Engine modules:
- Audio: remove AudioSource/Listener components (they belong in Components/), add IAudioEffect.h
- Components: add AudioSourceComponent.h and AudioListenerComponent.h
- Math: remove non-existent OBB.h
- Resources: fix DependencyGraph.h -> ResourceDependencyGraph.h
- Threading: add TaskSystemConfig.h
- RHI: remove incorrect RHIDescriptor.h (already covered by RHIDescriptorPool.h)

Backend fixes:
- OpenGL: add OpenGLScreenshot.h
- D3D12: fix file order (D3D12Enum.h before D3D12Types.h)

docs/api/resources/texture-import-settings/loadfromjson.md

@@ -0,0 +1,28 @@
+# TextureImportSettings::LoadFromJSON
+
+```cpp
+bool LoadFromJSON(const Containers::String& json) override;
+```
+
+从 JSON 字符串加载导入设置。
+
+**参数：**
+- `json` - JSON 格式的设置字符串
+
+**返回：** `bool` - 加载是否成功
+
+**注意：** 当前为 stub 实现，始终返回 `false`。
+
+**线程安全：** ✅
+
+**示例：**
+
+```cpp
+TextureImportSettings settings;
+bool success = settings.LoadFromJSON(R"({"textureType":1,"sRGB":true})");
+// 当前实现返回 false
+```
+
+## 相关文档
+
+- [TextureImportSettings 总览](textureimportsettings.md) - 返回类总览