fix: implementasi FilamentUser interface agar panel bisa diakses di production

- Tambah FilamentUser interface di User model
- Tambah canAccessPanel() method
- Tambah VoteObserver: broadcast notifikasi ke semua user saat vote baru
- Tambah NotificationService::toAll()
- Fix Vote model: auto-fill created_by via booted()
- Fix CashRecordObserver: fallback created_by untuk Vote

app/Providers/AppServiceProvider.php

@@ -5,9 +5,11 @@ namespace App\Providers;
 use App\Models\Activity;
 use App\Models\CashRecord;
 use App\Models\User;
+use App\Models\Vote;
 use App\Observers\ActivityObserver;
 use App\Observers\CashRecordObserver;
 use App\Observers\UserObserver;
+use App\Observers\VoteObserver;
 use Illuminate\Support\ServiceProvider;
 
 class AppServiceProvider extends ServiceProvider
@@ -17,5 +19,6 @@ class AppServiceProvider extends ServiceProvider
         User::observe(UserObserver::class);
         CashRecord::observe(CashRecordObserver::class);
         Activity::observe(ActivityObserver::class);
+        Vote::observe(VoteObserver::class);
     }
 }