server : (webui) Enable communication with parent html (if webui is in iframe) (#11940)

* Webui: Enable communication with parent html (if webui is in iframe):
- Listens for "setText" command from parent with "text" and "context" fields. "text" is set in inputMsg, "context" is used as hidden context on the following requests to the llama.cpp server
- On pressing na Escape button sends command "escapePressed" to the parent

Example handling from the parent html side:
- Send command "setText" from parent html to webui in iframe:
const iframe = document.getElementById('askAiIframe');
if (iframe) {
	iframe.contentWindow.postMessage({ command: 'setText', text: text, context: context }, '*');
}

- Listen for Escape key from webui on parent html:
// Listen for escape key event in the iframe
window.addEventListener('keydown', (event) => {
	if (event.key === 'Escape') {
		// Process case when Escape is pressed inside webui
	}
});

* Move the extraContext from storage to app.context.

* Fix formatting.

* add Message.extra

* format + build

* MessageExtraContext

* build

* fix display

* rm console.log

---------

Co-authored-by: igardev <ivailo.gardev@akros.ch>
Co-authored-by: Xuan Son Nguyen <son@huggingface.co>

examples/server/webui/src/utils/misc.ts

@@ -53,12 +53,23 @@ export const copyStr = (textToCopy: string) => {
 
 /**
  * filter out redundant fields upon sending to API
+ * also format extra into text
  */
 export function normalizeMsgsForAPI(messages: Readonly<Message[]>) {
   return messages.map((msg) => {
+    let newContent = '';
+
+    for (const extra of msg.extra ?? []) {
+      if (extra.type === 'context') {
+        newContent += `${extra.content}\n\n`;
+      }
+    }
+
+    newContent += msg.content;
+
     return {
       role: msg.role,
-      content: msg.content,
+      content: newContent,
     };
   }) as APIMessage[];
 }