# Bulk Link Books

Link multiple books to media items at once.

**Endpoint**: `POST /api/sync/bulk-link-books`
**Auth**: Required
**Content-Type**: `application/json`

## Request Body

| Field | Type  | Required | Description                      |
| ----- | ----- | -------- | -------------------------------- |
| links | array | Yes      | Array of book-media link objects |

Each link object contains:
| Field | Type | Required | Description |
|--------|------|-----------|-------------|
| device_id | string (UUID) | Yes | Device UUID |
| book_id | string (UUID) | Yes | Book ID from device |
| media_item_id | string (UUID) | Yes | Media item UUID to link to |

### Example Request

```json
{
  "links": [
    {
      "device_id": "550e8400-e29b-41d4-a716-446655440000",
      "book_id": "book-123",
      "media_item_id": "660e8400-e29b-41d4-a716-446655440001"
    },
    {
      "device_id": "550e8400-e29b-41d4-a716-446655440000",
      "book_id": "book-456",
      "media_item_id": "770e8400-e29b-41d4-a716-446655440002"
    }
  ]
}
```

## Response (200 OK)

```json
{
  "message": "Books linked successfully",
  "linked_count": 2,
  "failed_count": 0
}
```

## Error Responses

| Code | Description                           |
| ---- | ------------------------------------- |
| 400  | Invalid request data                  |
| 401  | Invalid or expired token              |
| 404  | Device, book, or media item not found |
