Salmanap/chrome extension routing (#511)

* first commit of the chatGPT selector

* stashing changes as checkpoint

* pending changes for chrome extension

* commiting a working version

* converting conversation into messages object

* working version of the extension

* working version with fixed styling and better tested

* fixed the issue that the drop down was too small, and fixed the issue where the route was not displayed on the screen

* updating folder with README.md

* fixes for default model, and to update the manifest.json file

* made changes to the dark mode. improved styles

* fix installation bug

* added dark mode

* fixed default model selection

* fixed the scrolling issue

* Update README.md

* updated content.js to update the labels even when default model

* fixed readme

* upddated the title of the packag

* removing the unnecessary permissions

---------

Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-329.local>
Co-authored-by: cotran <cotran2@utexas.edu>
Co-authored-by: Shuguang Chen <54548843+nehcgs@users.noreply.github.com>

demos/use_cases/chatgpt-preference-model-selector/src/scripts/pageFetchOverride.js

@@ -0,0 +1,61 @@
+(function() {
+  const TAG = '[ModelSelector][Page]';
+  console.log(`${TAG} installing fetch override`);
+
+  const origFetch = window.fetch;
+  window.fetch = async function(input, init = {}) {
+
+    const urlString = typeof input === 'string' ? input : input.url;
+    const urlObj = new URL(urlString, window.location.origin);
+    const pathname = urlObj.pathname;
+    console.log(`${TAG} fetch →`, pathname);
+
+    const method = (init.method || 'GET').toUpperCase();
+    if (method === 'OPTIONS') {
+      console.log(`${TAG} OPTIONS request → bypassing completely`);
+      return origFetch(input, init);
+    }
+
+    // Only intercept conversation fetches
+    if (pathname === '/backend-api/conversation') {
+      console.log(`${TAG} matched → proxy via content script`);
+
+      const { port1, port2 } = new MessageChannel();
+
+      // ✅ Remove non-cloneable properties like 'signal'
+      const safeInit = { ...init };
+      delete safeInit.signal;
+
+      // Forward the fetch details to the content script
+      window.postMessage({
+        type: 'ARCHGW_FETCH',
+        url: urlString,
+        init: safeInit
+      }, '*', [port2]);
+
+      // Return a stream response that the content script will fulfill
+      return new Response(new ReadableStream({
+        start(controller) {
+          port1.onmessage = ({ data }) => {
+            if (data.done) {
+              controller.close();
+              port1.close();
+            } else {
+              controller.enqueue(new Uint8Array(data.chunk));
+            }
+          };
+        },
+        cancel() {
+          port1.close();
+        }
+      }), {
+        headers: { 'Content-Type': 'text/event-stream' }
+      });
+    }
+
+    // Otherwise, pass through to the original fetch
+    return origFetch(input, init);
+  };
+
+  console.log(`${TAG} fetch override installed`);
+})();