Error: La

## Error

```
La
```

## Stack trace

```
/users/sign_up:460
/users/sign_up:194 in Ui
/users/sign_up:195
```

## Tracking Details
- **Project**: exercism-js
- **Sentry**: [Error: La](https://thalamus-ai.sentry.io/issues/144262589/)
- **Culprit**: ?(users/sign_up)
- **First seen:** Sep 1, 2026

Start with the Sentry report and the stack trace, then inspect users/sign_up at lines 460, 194, and 195. Reproduce the “La” error for exercism-js and identify its cause; done means the error no longer occurs when the same signup flow is exercised.

Written by the indexing model from the issue text.