Fix silent market CSV export

src/content/index.ts

@@ -39,15 +39,18 @@ export async function bootContentScript(
     return null;
   }
 
+  installMarketPageBridge(currentDocument);
+
   const authState = await readAuthState(sendAuthMessage);
   if (!authState?.isAuthenticated) {
+    await waitForBodyReady(currentDocument, currentWindow);
     renderMarketAuthGate(currentDocument, currentWindow);
     return {
       ready: Promise.resolve()
     };
   }
 
-  installMarketPageBridge(currentDocument);
+  await waitForBodyReady(currentDocument, currentWindow);
 
   return controllerFactory({
     document: currentDocument,
@@ -144,6 +147,24 @@ function createRuntimeMessageSender(): (message: unknown) => Promise<unknown> {
   };
 }
 
+async function waitForBodyReady(document: Document, currentWindow: Window): Promise<void> {
+  if (document.body) {
+    return;
+  }
+
+  await new Promise<void>((resolve) => {
+    const handleReady = () => {
+      if (document.body) {
+        document.removeEventListener("DOMContentLoaded", handleReady);
+        resolve();
+      }
+    };
+
+    document.addEventListener("DOMContentLoaded", handleReady);
+    currentWindow.setTimeout(handleReady, 0);
+  });
+}
+
 function downloadCsv(document: Document, window: Window, csv: string): void {
   const blob = new Blob(["\uFEFF", csv], {
     type: "text/csv;charset=utf-8"