fix: QR login now persists cookies, shows server-generated QR image, passes timestamp

- Auth router accepts CookieStore and persists cookies on login
- NeteaseProvider passes timestamp to prevent cached QR responses
- QR image from server used directly (qrimg field)
- Cookie saved to disk on confirmed QR scan

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

src/index.ts

@@ -58,6 +58,7 @@ async function main() {
     database: db,
     config,
     logger,
+    cookieStore,
     staticDir: STATIC_DIR,
   });
   await webServer.start();