✨ Introduce places:cleanup command to remove unused venues and cities

- 🧹 Add `places:cleanup` console command for dry-run and forced deletion of venues (without course/bitcoin events) and cities (without venues/meetups).
- 🧪 Add feature tests for `places:cleanup`, covering dry-run, forced deletion, and scenarios ensuring retention of dependent records.
- ➕ Add `bitcoinEvents` relationship to `Venue` model to support cleanup logic.

app/Models/Venue.php

@@ -102,4 +102,9 @@ class Venue extends Model implements HasMedia
     {
         return $this->hasMany(CourseEvent::class);
     }
+
+    public function bitcoinEvents(): HasMany
+    {
+        return $this->hasMany(BitcoinEvent::class);
+    }
 }