feat: Build Leaderboard Page (All-Time, Monthly, Weekly)

[Benjtalkshow]

Closes #94

PR Description: Build Leaderboard Page

Goal

Implement a comprehensive Leaderboard page to display top contributors by reputation with various time filters and category tabs.

Changes

• New Route: Created /leaderboard route integrated into MainWindow.
• Navigation: Added "Leaderboard" to the main navigation menu.
• UI Component: Built a premium Leaderboard page featuring:
  • Top 100 users by reputation scores.
  • Time Period Filters: All-Time, This Year, This Month, This Week.
  • Category Tabs: Overall, Reports, Vulnerabilities, Community (comments).
  • Contributor Details: Rank (with trophy icons for top 3), Avatar, Username, Reputation, and Badge Count.
  • Trend Indicators: Up/Down/Neutral arrows (↑↓) showing position changes.
  • User Highlighting: Visual highlighting of the current user's entry.
  • Sticky Header: Optimized table for scrolling with a persistent header.
• Caching: Implemented frontend-side caching with a 5-minute TTL to simulate scheduled data refreshes.
• Models: Defined LeaderboardEntry, TimePeriod, and LeaderboardCategory models.

Blocked Status

Important

I am aware that this task is currently blocked by #92. However, I have completed the implementation based on the current system and am submitting this as a Draft PR to ensure completion before the deadline. Once #92 is resolved, I will update the data fetching logic to integrate with the new backend endpoints.

Acceptance Criteria Checklist

• Create /leaderboard route
• Show top 100 users by reputation
• Add time period filters: All-Time, This Year, This Month, This Week
• Display rank, avatar, username, reputation, badge count
• Highlight current user's position
• Create leaderboard caching with scheduled refresh
• Add category tabs: Overall, Reports, Vulnerabilities, Community
• Show position change indicators (↑↓)
• Stick to existing design system

Video Proof