Rebrand as Playlink with a new sunset theme

- Name: Playlink in the UI, page title, footer, messages and README
  (file names like playlink.db and .playlink-trash are unchanged).
- Theme: plum-black surfaces with a coral-to-pink accent, a soft glow
  behind the page, gradient primary buttons, toggles and progress bars,
  accent focus rings and slim scrollbars.
- New logo (beamed notes on the brand gradient) and a Play/link wordmark.
- Inter variable font, bundled so it works under the strict CSP.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/package-lock.json

@@ -8,6 +8,7 @@
       "name": "playlink-web",
       "version": "0.1.0",
       "dependencies": {
+        "@fontsource-variable/inter": "^5.3.0",
         "@tanstack/react-query": "^5.103.2",
         "lucide-react": "^1.47.0",
         "react": "^19.3.0",
@@ -23,6 +24,15 @@
         "vite": "^8.3.0"
       }
     },
+    "node_modules/@fontsource-variable/inter": {
+      "version": "5.3.0",
+      "resolved": "https://registry.npmjs.org/@fontsource-variable/inter/-/inter-5.3.0.tgz",
+      "integrity": "sha512-OupL48va4JNofb97w6NYeF9S7W/kHNKM0Er8Dem5nqi4jeOLrVJDoE8tZEpnMJmtkvNbB1EIPPwHcdkF6b1oUA==",
+      "license": "OFL-1.1",
+      "funding": {
+        "url": "https://github.com/sponsors/ayuhito"
+      }
+    },
     "node_modules/@jridgewell/gen-mapping": {
       "version": "0.3.13",
       "resolved": "https://registry.npmjs.org/@jridgewell/gen-mapping/-/gen-mapping-0.3.13.tgz",