## Summary
- trust the new Railway Go backend in the standalone Auth UI
- preserve exact-origin validation for untrusted redirects
- document the root cause, delivery plan, and production validation path
## Root cause
The Auth UI rejected
`api_server_url=https://airi-server-next.up.railway.app`, fell back to
the legacy API, and surfaced `Load failed` at the browser CORS boundary.
## Test plan
- focused bootstrap-context tests: 6/6
- complete Auth UI suite: 27/27
- `vue-tsc --noEmit`
- production Vite build
- emitted bundle contains the exact new backend origin