portal-api/app/Models/InvoiceAttachment.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Support\Facades\Storage;

class InvoiceAttachment extends Model
{
    public const TYPE_PAYMENT_PROOF = 'payment_proof';
    public const TYPE_DEPLOYMENT = 'deployment';

    protected $table = 'invoice_attachments';

    protected $guarded = [];

    protected $appends = ['url'];

    public function invoice()
    {
        return $this->belongsTo(Invoice::class);
    }

    public function getUrlAttribute(): string
    {
        return Storage::disk($this->disk)->url($this->path);
    }
}