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/index.html

@@ -917,7 +917,6 @@ footer a:hover{color:var(--laranja2)}
             <div class="trocouCam" id="avisoTipo" style="display:none"></div>
             <div class="recusa" id="recusa" style="display:none"></div>
             <div id="lista"></div>
-            <p class="avisoEnvio" id="avisoEnvio" role="note" hidden></p>
             <div class="zona" id="zona" tabindex="0" role="button">
               <div class="ico"><svg class="ic" viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"/><path d="m17 8-5-5-5 5"/><path d="M12 3v12"/></svg></div>
               <b id="zTit">Arraste aqui</b><span id="zSub"></span>