feat(homepage): an Audiobookshelf card on the admin page

Admin category, Media Library Apps section, LAN-direct url and probe like Tautulli:
the service is internal-only, with no vhost and no DNS name, so it earns a card and
no public link. The art is a mono-ab.svg monogram in the existing hexagon family.

Card counts in the e2e specs come from the live registry, so this entry is the test
update as well as the page change - and the admin walk will follow the link, which
is why the service deploys before the homepage ships.

shared/homepage/img/apps/mono-ab.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 96 96"><polygon points="48,6 86,27 86,69 48,90 10,69 10,27" fill="#1c1300" stroke="#3fc1c9" stroke-width="3"/><text x="48" y="60" font-family="monospace" font-size="30" font-weight="bold" fill="#3fc1c9" text-anchor="middle">AB</text></svg>