fix: replace the wordmark favicon with a legible icon set (#164)

The favicon was the full 1099x406 logo lockup, which renders 16x6 in a
tab - an illegible smear - in near-black on a transparent background, so
it vanished entirely on a dark tab strip. There was also no favicon.ico,
leaving Safari before 26, feed readers and the favicon services with
nothing, and no apple-touch-icon.

Crop to the dot matrix from the logo, the only part that survives 16px,
on a square viewBox. The dots take the accent blue and swap to the dark
accent through a media query inside the SVG. Add a compiled favicon.ico
with 16/32/48 entries at the stable root URL, and an opaque 180x180
apple touch icon on the brand cream, since iOS composites transparency
onto black.

The new SVG lands on a fresh URL because Safari's favicon cache only
refreshes dependably on a URL change.

Author: alvgaona

astro.config.mjs

@@ -12,7 +12,17 @@ export default defineConfig({
       title: "RoboStack",
       description:
         "Run any ROS distro in an isolated, per-project environment. On Linux, macOS and Windows.",
-      favicon: "/favicon.svg",
+      favicon: "/icon.svg",
+      head: [
+        {
+          tag: "link",
+          attrs: { rel: "icon", href: "/favicon.ico", sizes: "32x32" },
+        },
+        {
+          tag: "link",
+          attrs: { rel: "apple-touch-icon", href: "/apple-touch-icon.png" },
+        },
+      ],
       social: [
         {
           icon: "github",