webui : Prevent rerendering on textarea input (#12299)

* webui: Make textarea uncontrolled to eliminate devastating lag

* Update index.html.gz

* use signal-style implementation

* rm console log

* no duplicated savedInitValue set

---------

Co-authored-by: Xuan Son Nguyen <son@huggingface.co>

examples/server/webui/src/utils/llama-vscode.ts

@@ -1,5 +1,6 @@
 import { useEffect, useState } from 'react';
 import { MessageExtraContext } from './types';
+import { OptimizedTextareaValue } from '../components/ChatScreen';
 
 // Extra context when using llama.cpp WebUI from llama-vscode, inside an iframe
 // Ref: https://github.com/ggml-org/llama.cpp/pull/11940
@@ -14,10 +15,7 @@ interface SetTextEvData {
  * window.postMessage({ command: 'setText', text: 'Spot the syntax error', context: 'def test()\n  return 123' }, '*');
  */
 
-export const useVSCodeContext = (
-  inputRef: React.RefObject<HTMLTextAreaElement>,
-  setInputMsg: (text: string) => void
-) => {
+export const useVSCodeContext = (textarea: OptimizedTextareaValue) => {
   const [extraContext, setExtraContext] = useState<MessageExtraContext | null>(
     null
   );
@@ -27,20 +25,20 @@ export const useVSCodeContext = (
     const handleMessage = (event: MessageEvent) => {
       if (event.data?.command === 'setText') {
         const data: SetTextEvData = event.data;
-        setInputMsg(data?.text);
+        textarea.setValue(data?.text);
         if (data?.context && data.context.length > 0) {
           setExtraContext({
             type: 'context',
             content: data.context,
           });
         }
-        inputRef.current?.focus();
+        textarea.focus();
       }
     };
 
     window.addEventListener('message', handleMessage);
     return () => window.removeEventListener('message', handleMessage);
-  }, [inputRef, setInputMsg]);
+  }, [textarea]);
 
   // Add a keydown listener that sends the "escapePressed" message to the parent window
   useEffect(() => {