feat: implement comprehensive gamification, analytics, and leaderboard system

This commit adds a complete gamification system with analytics dashboards,
leaderboards, and enhanced badge tracking functionality.

Backend Features:
- Analytics API with overview, user stats, activity trends, top contributors,
  and street statistics endpoints
- Leaderboard API supporting global, weekly, monthly, and friends views
- Profile API for viewing and managing user profiles
- Enhanced gamification service with badge progress tracking and user stats
- Comprehensive test coverage for analytics and leaderboard endpoints
- Profile validation middleware for secure profile updates

Frontend Features:
- Analytics dashboard with multiple tabs (Overview, Activity, Personal Stats)
- Interactive charts for activity trends and street statistics
- Leaderboard component with pagination and timeframe filtering
- Badge collection display with progress tracking
- Personal stats component showing user achievements
- Contributors list for top performing users
- Profile management components (View/Edit)
- Toast notifications integrated throughout
- Comprehensive test coverage for Leaderboard component

Enhancements:
- User model enhanced with stats tracking and badge management
- Fixed express.Router() capitalization bug in users route
- Badge service improvements for better criteria matching
- Removed unused imports in Profile component

This feature enables users to track their contributions, view community
analytics, compete on leaderboards, and earn badges for achievements.

🤖 Generated with OpenCode

Co-Authored-By: AI Assistant <noreply@opencode.ai>

backend/__tests__/jest.preSetup.js

@@ -1,4 +1,18 @@
 // This file runs before any modules are loaded
+
+// Set test environment variables FIRST (before any module loads)
+// Must be at least 32 chars for validation
+process.env.NODE_ENV = 'test';
+process.env.JWT_SECRET = 'test-jwt-secret-for-testing-purposes-that-is-long-enough';
+process.env.COUCHDB_URL = 'http://localhost:5984';
+process.env.COUCHDB_DB_NAME = 'test-adopt-a-street';
+process.env.PORT = '5001';
+
+// Mock dotenv to prevent .env file from overriding test values
+jest.mock('dotenv', () => ({
+  config: jest.fn()
+}));
+
 // Mock axios first since couchdbService uses it
 jest.mock('axios', () => ({
   create: jest.fn(() => ({