- Add completeEvent endpoint to backend API
- Create EventCompletionForm component with litter quantity input and photo upload
- Update EventDetailModal to show completion form for organizers
- Add isOrganizer check in EventsPage
- Update event service to support completion
- Display completion data (litter collected, photos) for completed events
- Add findOrCreateUser helper function to handle Clerk ID to database ID mapping
- Update all authenticated endpoints to convert Clerk ID to database user ID
- Ensures events can be created and managed by authenticated users
- Matches pattern used in reportController