feat: the upload bar says how long is left, not a notice before it

The product page's notice about the upload time is gone. The cart's upload
bar now reads "Enviando seus arquivos · faltam cerca de 6 min", measured
from the upload's own speed (a range from the size for the first seconds),
with a line saying the time depends on the internet and to keep the page
open. The header and the pay button show the same time instead of a
percentage.

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

web/site-cart.js

@@ -77,7 +77,6 @@ function pintaPedido(){
   if(pedido.length || itemAtual) $('carr').classList.add('on');
   if($('cartN')){ $('cartN').textContent=noCarrinho>99?'99+':noCarrinho; $('cartN').hidden=!noCarrinho;
     $('cartLink').setAttribute('aria-label','Carrinho, '+noCarrinho+(noCarrinho===1?' item':' itens')); }
-  pintaAvisoEnvio();
   window.dispatchEvent(new Event('dtf-cart-changed'));
 }