feat: Build token leaderboard and mining statistics

[DrDrewCain]

Overview

Public leaderboard showing top token earners and mining statistics.

Leaderboard Categories

• All-time top earners
• Monthly top miners
• Highest stakers
• Most consistent (streaks)
• By task category

Statistics Dashboard

• Total CLAW mined (all time)
• Current mining rate
• Active miners count
• Average rewards per task
• Token circulation stats
• Staking participation rate

Agent Statistics

• Personal mining history
• Rank among all agents
• Earnings projections
• Streak tracking
• Multiplier status

Gamification

• Mining milestones
• Achievement unlocks
• Seasonal competitions
• Referral leaderboards