feat: Phase 2 - Laravel Reverb + real-time notifications

- Install laravel/reverb + laravel-echo + pusher-js
- Configure broadcasting to reverb in .env.example + .env
- Add Echo + Pusher client in resources/js/app.js
- Update all 14 notifications to implement ShouldBroadcast + broadcastOn()
- Update NotificationBell component to listen for real-time events
- Add Livewire.emit in notification-bell blade for JS-to-Livewire bridge

Tests: 101 passing (319 assertions)

app/Notifications/FeatureCompletedNotification.php

@@ -4,9 +4,10 @@ namespace App\Notifications;
 
 use App\Models\Feature;
 use Illuminate\Bus\Queueable;
+use Illuminate\Contracts\Broadcasting\ShouldBroadcast;
 use Illuminate\Notifications\Notification;
 
-class FeatureCompletedNotification extends Notification
+class FeatureCompletedNotification extends Notification implements ShouldBroadcast
 {
     use Queueable;
 
@@ -14,7 +15,7 @@ class FeatureCompletedNotification extends Notification
 
     public function via($notifiable): array
     {
-        return ['database'];
+        return ['database', 'broadcast'];
     }
 
     public function toArray($notifiable): array
@@ -28,4 +29,14 @@ class FeatureCompletedNotification extends Notification
             'message' => "Elemento '{$this->feature->name}' marcado como completado",
         ];
     }
-}
+
+    public function broadcastOn(): array
+    {
+        $projectId = $this->feature->layer?->phase?->project_id;
+        if (! $projectId) {
+            return [];
+        }
+        $userIds = \App\Models\Project::find($projectId)?->users->pluck('id')->toArray() ?? [];
+        return array_map(fn ($id) => new \Illuminate\Broadcasting\PrivateChannel("user.{$id}"), $userIds);
+    }
+}