fix: add support for Clerk IDs and activity endpoint

- Update getUserProfile to accept both database ID and Clerk ID
- Update getUserReports to handle Clerk IDs
- Update getUserEvents to handle Clerk IDs
- Add getUserActivity endpoint to return timeline of user actions
- Add activity route GET /api/users/:id/activity
- Fix TypeScript errors with const assertions

This fixes 404 errors when frontend uses Clerk IDs to fetch user data

server/src/routes/userRoutes.ts

@@ -11,6 +11,7 @@ router.patch('/:id', requireAuth, userController.updateUserProfile.bind(userCont
 // User reports and events
 router.get('/:id/reports', userController.getUserReports.bind(userController));
 router.get('/:id/events', userController.getUserEvents.bind(userController));
+router.get('/:id/activity', userController.getUserActivity.bind(userController));
 
 // Notification preferences
 router.patch('/:id/preferences', requireAuth, userController.updateNotificationPreferences.bind(userController));