- Add Cancel Event button in event detail modal for organizers
- Show cancel button both before and after event date (if not completed)
- Add confirmation dialog before cancelling
- Update event status to 'cancelled' when cancelled
- Only organizers can cancel their events
- 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
- Create EventForm component with date/time picker and map-based location selection
- Implement EventList component with status badges and participant counts
- Add EventFilters component for filtering by status and date range
- Create EventDetailModal with registration functionality and event details
- Build eventService for API calls (getEvents, createEvent, register, etc.)
- Update EventsPage with full event management UI
- Support event creation, listing, filtering, and registration
- Requirements: 4.1, 4.2, 4.3, 4.4
