fix: cors issues from preview fixed by changing embedder policies (#1056)

Author: wonderwhy-er

app/lib/webcontainer/index.ts

@@ -24,6 +24,7 @@ if (!import.meta.env.SSR) {
     Promise.resolve()
       .then(() => {
         return WebContainer.boot({
+          coep: 'credentialless',
           workdirName: WORK_DIR_NAME,
           forwardPreviewErrors: true, // Enable error forwarding from iframes
         });