feat: phone login via QR when the saved Mudfish login expires

When autologin is rejected the panel offers '휴대폰으로 로그인 (QR)'. It opens
a 5-minute LAN relay to the launcher UI guarded by a one-time token (first
phone to open the QR URL is the only client allowed) and shows the URL as a
QR code. The relay closes as soon as a new session appears, on cancel, on
expiry, and on unload.

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

package.json

@@ -20,6 +20,7 @@
   },
   "dependencies": {
     "@decky/api": "^1.1.3",
+    "qrcode-generator": "1.4.4",
     "react-icons": "^5.3.0",
     "tslib": "^2.7.0"
   },