[Feature] CSV/Excel Export

[devalade]

Description

Add export functionality to the generated index page.

Proposed Syntax

php artisan crudify:generate Product --fields="name:string,price:decimal" --export

Features

• Export filtered/sorted results to CSV
• Export to Excel (via maatwebsite/excel or spatie/simple-excel)
• Select columns to export
• Export with relationships (e.g., include user name instead of user_id)
• Background export for large datasets (queue job)

Generated Code

// In Livewire Index
public function export(string $format = 'csv'): StreamedResponse
{
    return response()->streamDownload(function () use ($format) {
        $query = Product::query()->with(['user'])->when($this->search, ...);
        
        if ($format === 'csv') {
            $file = fopen('php://output', 'w');
            fputcsv($file, ['Name', 'Price', 'User']);
            foreach ($query->cursor() as $product) {
                fputcsv($file, [$product->name, $product->price, $product->user?->name]);
            }
            fclose($file);
        }
    }, "products-".now()->format('Y-m-d').".csv");
}