/.rules/require_unique_id_props.mdc

```yaml
name: require-unique-id-props
description: Ensure unique key props are provided when mapping arrays to React elements
globs: ['**/*.tsx', '**/*.jsx']
alwaysApply: true
```

When mapping arrays to React elements, each element must have a unique key prop to help React efficiently update the DOM.

❌ Bad - Missing key prop:
```jsx
{items.map((item) => (
  <Link href={`/dashboard/${item.id}`}>
    <Card>{item.name}</Card>
  </Link>
))}
```

✅ Good - With key prop:
```jsx
{items.map((item) => (
  <Link key={item.id} href={`/dashboard/${item.id}`}>
    <Card>{item.name}</Card>
  </Link>
))}
```

Keys should be stable, predictable, and unique among siblings.