🚀 **Automate Meetup Activity Recalculation**

- Introduced `recalculateActivity` method in `Meetup` model to centralize activity and event timestamp updates.
- Added `MeetupEventObserver` to trigger activity recalculation on event save/delete.
- Updated `/meetups:update-activity` command to leverage the new model method for cleanup.
- Enhanced tests to cover various `MeetupEvent` scenarios affecting activity states.

app/Models/MeetupEvent.php

@@ -3,10 +3,13 @@
 namespace App\Models;
 
 use App\Enums\RecurrenceType;
+use App\Observers\MeetupEventObserver;
+use Illuminate\Database\Eloquent\Attributes\ObservedBy;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 
+#[ObservedBy([MeetupEventObserver::class])]
 class MeetupEvent extends Model
 {
     use HasFactory;