feat: implement user profile page with statistics, contribution map, and activity timeline

- Add userService for profile and activity API calls
- Create UserProfilePage with tabbed interface (overview, reports, events, activity)
- Display user statistics (reports count, events count, impact score)
- Implement personal contribution map showing all user report locations
- Add activity timeline with different activity types
- Enable profile editing for own profile (first name, last name, username)
- Update UserProfile component to link to profile page
- Add /profile/:userId route to App
- Install react-leaflet for map integration
- Requirements: 6.3, 6.4, 6.5

src/pages/index.ts

@@ -7,3 +7,4 @@ export { PhotoUploadDemo } from './PhotoUploadDemo';
 export { default as LocationSelectorDemo } from './LocationSelectorDemo';
 export { ReportDetailDemo } from './ReportDetailDemo';
 export { WhyCleanPage } from './WhyCleanPage';
+export { UserProfilePage } from './UserProfilePage';