feat: implement report submission and display (task 9)

- Created reportService for API interactions (upload, create, get, verify, dispute)
- Built ReportDetailModal component with photo gallery and verification UI
- Updated ReportForm with actual API submission and progress tracking
- Added error handling and success states
- Created ReportDetailDemo page to showcase modal functionality
- Added route for demo page at /demo/report-detail
- Exported services through index file for cleaner imports
- Documented implementation in SUBMISSION_IMPLEMENTATION.md

Requirements fulfilled: 1.8, 7.4

.kiro/specs/beach-litter-mapping/tasks.md

@@ -66,7 +66,7 @@
   - Create environmental concerns section
   - _Requirements: 1.6, 1.7, 9.1, 9.2_
 
-- [ ] 9. Implement report submission and display
+- [x] 9. Implement report submission and display
   - Connect form to API endpoint for report creation
   - Handle submission success and error states
   - Create report detail modal/popup component