Redesign media card with album art, 7-button transport, and Wolf Kit icons

Replace media card with full redesign: rectangular album art (180px) with
background fetcher, track title + artist display, volume icon + percentage,
progress bar, and 7-button transport row (playlist, skip-back, seek-back,
play/pause, seek-forward, skip-forward, search) with Apple-style opacity
focus. Add scroll-wheel seek and back-button card mode exit.

Replace all media SVG icons with Wolf Kit Rounded Line icons from SVGRepo
(CC Attribution, author: thewolfkit): play, pause, skip-back, skip-forward,
seek-back, seek-forward, playlist (line-3), search, volume.

Fix vacuum card: add config fallback for custom button cards, expand entity
subscriptions for derived entities, fix clean command segment format, remove
fill, increase image size to 160px.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

assets/ui-icons/skip-back.svg

@@ -0,0 +1,4 @@
+<svg width="128" height="128" color="#fff" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path fill-rule="evenodd" clip-rule="evenodd" d="M17.8906 4.20444C19.2197 3.31836 21 4.27115 21 5.86854V18.1315C21 19.7289 19.2197 20.6817 17.8906 19.7956L8.69337 13.6641C7.50591 12.8725 7.50591 11.1276 8.69337 10.3359L17.8906 4.20444ZM19 5.86854L9.80277 12L19 18.1315V5.86854Z" fill="currentColor"/>
+<path d="M5 5C5 4.44772 4.55228 4 4 4C3.44772 4 3 4.44772 3 5V19C3 19.5523 3.44772 20 4 20C4.55228 20 5 19.5523 5 19V5Z" fill="currentColor"/>
+</svg>