Error: pa

## Error

```
pa
```

## Stack trace

```
/users/sign_up:415
```

## Tracking Details
- **Project**: exercism-js
- **Sentry**: [Error: pa](https://thalamus-ai.sentry.io/issues/146406561/)
- **Culprit**: ?(users/sign_up)
- **First seen:** Sep 11, 2026

Start with the Sentry report linked in the issue and inspect the /users/sign_up:415 stack-trace location. Determine what produces the “pa” error for the exercism-js project, then verify that the sign-up flow no longer emits this error.

Written by the indexing model from the issue text.