feat: add QR code login for NetEase/QQ Music accounts in Settings page

- QR code generated client-side via qrcode library
- Auto-polls backend every 2s for scan status
- Shows waiting/scanned/confirmed/expired states
- Falls back to cookie paste method
- Auth status check on page load

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web/package.json

@@ -9,18 +9,20 @@
     "preview": "vite preview"
   },
   "dependencies": {
-    "vue": "^3.5.0",
-    "vue-router": "^4.5.0",
-    "pinia": "^3.0.0",
+    "@iconify/vue": "^4.3.0",
     "axios": "^1.14.0",
     "node-vibrant": "^4.0.3",
-    "@iconify/vue": "^4.3.0"
+    "pinia": "^3.0.0",
+    "qrcode": "^1.5.4",
+    "vue": "^3.5.0",
+    "vue-router": "^4.5.0"
   },
   "devDependencies": {
-    "vite": "^6.3.0",
+    "@types/qrcode": "^1.5.6",
     "@vitejs/plugin-vue": "^5.2.0",
-    "typescript": "^5.8.0",
     "sass": "^1.87.0",
+    "typescript": "^5.8.0",
+    "vite": "^6.3.0",
     "vue-tsc": "^2.2.0"
   }
 }