feat: complete monorepo structure with frontend and shared resources

- Add complete backend/ directory with full Django application
- Add frontend/ directory with Vite + TypeScript setup ready for Next.js
- Add comprehensive shared/ directory with:
  - Complete documentation and memory-bank archives
  - Media files and avatars (letters, park/ride images)
  - Deployment scripts and automation tools
  - Shared types and utilities
- Add architecture/ directory with migration guides
- Configure pnpm workspace for monorepo development
- Update .gitignore to exclude .django_tailwind_cli/ build artifacts
- Preserve all historical documentation in shared/docs/memory-bank/
- Set up proper structure for full-stack development with shared resources

backend/apps/parks/signals.py

@@ -0,0 +1,34 @@
+from django.db.models.signals import post_save, post_delete
+from django.dispatch import receiver
+from django.db.models import Q
+
+from apps.rides.models import Ride
+from .models import Park
+
+
+def update_park_ride_counts(park):
+    """Update ride_count and coaster_count for a park"""
+    operating_rides = Q(status="OPERATING")
+
+    # Count total operating rides
+    ride_count = park.rides.filter(operating_rides).count()
+
+    # Count total operating roller coasters
+    coaster_count = park.rides.filter(operating_rides, category="RC").count()
+
+    # Update park counts
+    Park.objects.filter(id=park.id).update(
+        ride_count=ride_count, coaster_count=coaster_count
+    )
+
+
+@receiver(post_save, sender=Ride)
+def ride_saved(sender, instance, **kwargs):
+    """Update park counts when a ride is saved"""
+    update_park_ride_counts(instance.park)
+
+
+@receiver(post_delete, sender=Ride)
+def ride_deleted(sender, instance, **kwargs):
+    """Update park counts when a ride is deleted"""
+    update_park_ride_counts(instance.park)