🔧 chore(project): remove workspaces configuration and update UMD demo script

- 删除package.json中的workspaces配置
- 更新public/umd-demo.html中的SDK引用路径
  - 注释掉本地开发路径
  - 添加unpkg.com的CDN引用路径

package.json

@@ -3,9 +3,6 @@
   "version": "1.0.0",
   "license": "MIT",
   "type": "module",
-  "workspaces": [
-    "packages/*"
-  ],
   "scripts": {
     "dev": "vite",
     "dev:test": "vite --mode test",

public/umd-demo.html

@@ -407,7 +407,8 @@
     </div>
 
     <!-- 直接使用script标签加载UMD格式的SDK -->
-    <script src="/packages/stt-sdk-core/dist/index.umd.js"></script>
+    <!-- <script src="/packages/stt-sdk-core/dist/index.umd.js"></script> -->
+    <script src="https://unpkg.com/d8d-stt-sdk-core@1.0.0/dist/index.umd.js"></script>
 
     <script>
       let sdk = null