fix(webgpu): bump transformers.js to v3.8.1 to support lfm2 architecture

webgpu_prototype.html

@@ -27,7 +27,7 @@
 
 <script type="module">
     // Import transformers.js (v3 is required for WebGPU support for most modern models)
-    import { pipeline, env } from 'https://cdn.jsdelivr.net/npm/@huggingface/transformers@3.2.0';
+    import { pipeline, env } from 'https://cdn.jsdelivr.net/npm/@huggingface/transformers@3.8.1';
 
     const statusEl = document.getElementById('wg-status');
     const contextEl = document.getElementById('wg-context');