test: reload only after the cart is saved, instead of after 800 ms

The browser suite reloaded the page a fixed 800 ms after the last field
was typed. The cart save waits for typing to stop and writes the files to
the browser's storage, so under load the reload came first and the cart was
not recovered ("persistent cart recovery", and once "Inspected target
navigated or closed"). It now waits until the cart is in storage.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/browser_test.mjs

@@ -79,7 +79,12 @@ try{
   await site.fill('#fCnpj','11222333000181');
   await site.fill('#fZap','11999999999');
   await site.fill('#fMail','local-browser@example.test');
-  await pause(800);
+  // Reload only once the cart is in the browser's storage: the save waits for
+  // typing to stop and writes the files, so a fixed pause raced it.
+  await waitFor(()=>site.eval(`new Promise(done=>{const open=indexedDB.open('dtf-local-cart',1);
+    open.onerror=()=>done(false);
+    open.onsuccess=()=>{const all=open.result.transaction('cart').objectStore('cart').getAll();
+      all.onsuccess=()=>done(all.result.some(v=>v.items?.length===1));all.onerror=()=>done(false);};})`),'cart saved in the browser');
   await site.call('Page.reload');
   await waitFor(()=>site.eval('typeof pedido!=="undefined" && pedido.length===1'),'persistent cart recovery');
   // Reloading a product page reopens that product; the cart is its own page.