# Task ID: 32
# Title: Activity System (Daily Sign-in, Events)
# Status: pending
# Dependencies: 2, 5
# Priority: low
# Description: Implement a basic activity system to offer daily rewards (e.g., sign-in bonuses) and temporary event-based incentives.
# Details:
Backend: Design a flexible `Activity` data model (e.g., daily sign-in, specific win count event). Implement API endpoints for checking activity status and claiming rewards. Store user activity progress in MongoDB. Frontend: Create an 'Activities' section. Display current activities, progress, and a button to claim rewards. Implement daily sign-in UI with calendar.

# Test Strategy:
Test daily sign-in over several days. Verify rewards are granted correctly and progress is tracked. Test a temporary event (e.g., 'win 3 games for bonus') and ensure rewards are given upon completion.