docs(cloudxr): update INSTALL.md - SDK already in deps/cloudxr

Clarify that CloudXR.js SDK is already included in deps/cloudxr/,
no separate download needed. Users only need NGC credentials to
pull the cloudxr-runtime-early-access Docker image.

deps/cloudxr/INSTALL.md

@@ -90,8 +90,9 @@ nvm use 20
 
 ## 二、获取 CloudXR Early Access SDK
 
-1. 前往 [ngc.nvidia.com](https://ngc.nvidia.com) 获取 API Key
-2. 登录 NGC Docker registry：
+CloudXR.js SDK 已包含在本仓库 `deps/cloudxr/` 目录中，无需单独下载。
+
+只需登录 NGC Docker registry 以拉取 CloudXR Runtime 镜像：
 
 ```bash
 sudo docker login nvcr.io
@@ -99,14 +100,9 @@ sudo docker login nvcr.io
 # Password: <你的 NGC API Key>
 ```
 
-3. 下载 CloudXR.js SDK（从 NGC Early Access 页面获取），解压到：
-   ```
-   deps/cloudxr/
-   ├── nvidia-cloudxr-6.0.0-beta.tgz
-   ├── isaac/          # React Web App
-   ├── docs/
-   └── Dockerfile.wss.proxy
-   ```
+> NGC API Key 获取：[ngc.nvidia.com](https://ngc.nvidia.com) → 右上角头像 → Setup → Generate API Key
+>
+> Early Access 申请：[申请地址](https://developer.nvidia.com/cloudxr-sdk) — 申请通过后才能拉取 `cloudxr-runtime-early-access` 镜像。
 
 ---