Add Gruperly logotype and favicon from brand assets

Copy logotipo and isotipo assets to src/assets, expose them via
Eleventy passthrough, use the adaptive iso favicon in the head, and
replace the generic placeholder icons in header, footer and demo sidebar.

eleventy.config.js

@@ -5,6 +5,9 @@ export default function (eleventyConfig) {
     host: "0.0.0.0",
   });
 
+  // Copia los assets estáticos (logotipo, isotipo, favicon) a dist/assets.
+  eleventyConfig.addPassthroughCopy("src/assets");
+
   eleventyConfig.addFilter("formatPrice", (value, currency) => {
     const locale = currency === "ars" ? "es-AR" : "en-US";
     return new Intl.NumberFormat(locale).format(value);