construprogress/app/Notifications/TaskAssignedNotification.php

<?php

namespace App\Notifications;

use App\Models\Task;
use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Broadcasting\ShouldBroadcast;
use Illuminate\Notifications\Notification;

class TaskAssignedNotification extends Notification implements ShouldBroadcast
{
    use Queueable;

    public function __construct(public Task $task) {}

    public function via($notifiable): array
    {
        return ['database', 'broadcast'];
    }

    public function toArray($notifiable): array
    {
        return [
            'type' => 'task_assigned',
            'task_id' => $this->task->id,
            'project_id' => $this->task->project_id,
            'priority' => $this->task->priority,
            'message' => "Se te ha asignado la tarea '{$this->task->title}'",
        ];
    }

    public function broadcastOn(): array
    {
        return [new \Illuminate\Broadcasting\PrivateChannel('user.'.$this->task->assigned_to)];
    }
}