[codex] Remove COI service worker

docusaurus.config.js

@@ -40,12 +40,6 @@ const config = {
   deploymentBranch: 'gh-pages',
   trailingSlash: true,
 
-  // GitHub Pages can't set COOP/COEP response headers, which the embedded
-  // StackBlitz sandbox (WebContainers) requires for cross-origin isolation.
-  // This service worker shim injects them client-side.
-  // https://developer.stackblitz.com/platform/webcontainers/browser-support#embedding
-  scripts: ['/coi-serviceworker.js'],
-
   onBrokenLinks: 'throw',
   onBrokenMarkdownLinks: 'warn',
 

src/components/Sandbox/Iframe.tsx

@@ -8,10 +8,6 @@ export const Iframe = (
   return (
     <iframe
       loading="lazy"
-      // the page is cross-origin isolated (COEP) for the StackBlitz sandbox,
-      // which blocks cross-origin frames that don't serve COEP themselves;
-      // the credentialless attribute (Chromium) exempts this frame from that check
-      {...{ credentialless: 'true' }}
       {...props}
       onLoad={() => {
         setLoaded(true);
@@ -22,4 +18,4 @@ export const Iframe = (
       )}
     />
   );
-};
+};