Build Leaderboard Page with Rankings and Filters

**Title:** Create Global Leaderboard with Multiple Ranking Categories

## Problem Statement

Users lack competitive motivation and social engagement features. A leaderboard system would increase engagement, encourage replay, and create a sense of community, even with simulated data until backend integration.

## Proposed Solution

Implement a leaderboard system featuring:

* Global rankings with simulated user data
* Multiple ranking categories (All-Time, Weekly, Monthly)
* Category-specific leaderboards
* User's current rank display
* Top performers highlight
* Search functionality to find specific users

## Acceptance Criteria

### ✅ Leaderboard Display

* Table or card layout showing top 100 users
* Rank number, username, score, badge/avatar
* Highlight top 3 with special styling (gold/silver/bronze)
* Current user's rank highlighted if in top 100
* Smooth animations when data loads
* Responsive design for mobile/tablet/desktop

### ✅ Ranking Categories

* Tab navigation for All-Time, Weekly, Monthly
* Smooth transition animations between tabs
* Different ranking algorithms for each category
* Date range indicator for time-based rankings
* Auto-refresh on tab change

### ✅ Category Filters

* Dropdown or pills to filter by quiz category
* Filter by difficulty level
* "All Categories" default option
* Update rankings based on selected filters
* Show filter criteria in header

### ✅ User Position Card

* Fixed card showing current user's rank
* Display even if not in top 100
* Show rank, score, and percentile
* Highlight user's entry in table
* Scroll to user button if in visible list

### ✅ Search Functionality

* Search bar to find specific users
* Autocomplete suggestions
* Highlight found user in results
* Show user's full stats on selection

### ✅ Simulated Data

* Generate realistic leaderboard data
* Include usernames, avatars, scores
* Randomize data within realistic ranges
* Update data periodically (simulated real-time)
* Store in localStorage for persistence

### ✅ Animations

* Rank changes with slide animations
* New entries fade in
* Trophy/badge animations for top performers
* Smooth scroll to user's position