Add Snowflake casts to Eloquent Model example in docs

[joshhanley]

When using Snowflakes on models (especially with Livewire), it's good practice to add the snowflake casts to the model as per the bits documentation https://github.com/glhd/bits?tab=readme-ov-file#usage-with-eloquent-models

This PR updates the Snowflake Eloquent Model example to include the Snowflake casts.

use Glhd\Bits\Database\HasSnowflakes;
use Glhd\Bits\Snowflake;

class JobApplication extends Model
{
    use HasSnowflakes; // Add this to your model

    // Any attribute can be cast to a `Snowflake` (or `Sonyflake`)
    protected $casts = [
        'id' => Snowflake::class,
    ];
}