OperationError: The operation failed for an operation-specific reason

## Error

```
The operation failed for an operation-specific reason
```

## Stack trace

```
../app/javascript/components/dropdowns/Dropdown.tsx:16 in Dropdown
../node_modules/@sentry/react/src/errorboundary.tsx:101 in new ErrorBoundary
../node_modules/@tanstack/react-query/src/QueryClientProvider.tsx:29 in QueryClientProvider
```

## Tracking Details
- **Project**: exercism-js
- **Sentry**: [OperationError: The operation failed for an operation-specific reason](https://thalamus-ai.sentry.io/issues/133987687/)
- **Culprit**: id(app/javascript/components/dropdowns/useDropdown)
- **First seen:** Jul 13, 2026

Start by reading app/javascript/components/dropdowns/Dropdown.tsx at line 16 and the app/javascript/components/dropdowns/useDropdown entry point, then use the linked Sentry issue and stack trace to reproduce the failure. Done means the operation-specific error no longer occurs in this dropdown path and the relevant error behavior is verified.

Written by the indexing model from the issue text.