feat: implement user profile endpoints (task 31)

- Add GET /api/users/:id for profile retrieval with stats
- Add PATCH /api/users/:id for profile updates
- Add GET /api/users/:id/reports to fetch user's reports
- Add GET /api/users/:id/events to fetch user's events (registered & organized)
- Add PATCH /api/users/:id/preferences for notification settings
- Add POST /api/users/:id/calculate-impact for impact score calculation
- Create userService with all business logic
- Create userController with request handling
- Create userRoutes and register in main server
- Update frontend userService with new endpoints
- Add comprehensive documentation in USER_PROFILE_ENDPOINTS.md
- Add test script for manual endpoint testing

Requirements satisfied: 6.3, 6.4, 6.5, 10.4

server/src/routes/userRoutes.ts

@@ -0,0 +1,21 @@
+import { Router } from 'express';
+import { userController } from '../controllers/userController';
+import { requireAuth } from '../middleware/auth';
+
+const router = Router();
+
+// User profile endpoints
+router.get('/:id', userController.getUserProfile.bind(userController));
+router.patch('/:id', requireAuth, userController.updateUserProfile.bind(userController));
+
+// User reports and events
+router.get('/:id/reports', userController.getUserReports.bind(userController));
+router.get('/:id/events', userController.getUserEvents.bind(userController));
+
+// Notification preferences
+router.patch('/:id/preferences', requireAuth, userController.updateNotificationPreferences.bind(userController));
+
+// Impact score calculation
+router.post('/:id/calculate-impact', userController.calculateImpactScore.bind(userController));
+
+export default router;