Web: redesign, logo, PWA, QR codes, Spotify guidance

- Album-art-tinted cards that crossfade on song change, equalizer bars,
  live avatar rings, drifting ambient colour, Space Grotesk display font,
  brand purple-to-blue gradient from the logo
- Feed cards rise in and glide to new positions (motion); respects
  reduced-motion
- New logo as nav mark, favicon and Apple touch icon
- Installable PWA: manifest, maskable icons, small service worker
  (cached build assets + offline page), security headers
- Show-QR-code on your own profile; centred profile header with stats
- Settings explains connecting Spotify via Last.fm or ListenBrainz

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MzFywujuH9TiuXbr9vjoX8

apps/web/package.json

@@ -15,10 +15,11 @@
     "typescript": "~6.0.3"
   },
   "dependencies": {
+    "@musicshare/shared": "*",
+    "motion": "^14.0.0",
     "next": "^16.3.8",
     "react": "19.2.3",
     "react-dom": "19.2.3",
-    "swr": "^2.5.1",
-    "@musicshare/shared": "*"
+    "swr": "^2.5.1"
   }
 }