feat: Add event association to purchases; implement event relationship in models, update migration, and enhance tests

app/Domains/Event/Models/Event.php

@@ -3,6 +3,7 @@
 namespace App\Domains\Event\Models;
 
 use App\Domains\Catalog\Models\CatalogItem;
+use App\Domains\Purchase\Models\Purchase;
 use App\Domains\Tenant\Models\Tenant;
 use Illuminate\Database\Eloquent\Attributes\Fillable;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
@@ -38,4 +39,10 @@ class Event extends Model
     {
         return $this->hasMany(CatalogItem::class);
     }
+
+    /** @return HasMany<Purchase, $this> */
+    public function purchases(): HasMany
+    {
+        return $this->hasMany(Purchase::class);
+    }
 }