[Feature] Squad member leaderboard — rank by various stats

[grovecj]

Summary

Add an interactive leaderboard within the squad dashboard that ranks members by selectable stats.

Details

Leaderboard Features

• Stat selector dropdown: Choose which stat to rank by
  • K/D Ratio, Total Kills, Total Wins, Win %, Score/Min, Headshot %, Avg Kills/Game, Total Time Played
• Ranked table:
  • Position ([Infra] Terraform: GitHub repository configuration #1, [Infra] Terraform: Digital Ocean infrastructure #2, [Infra] Project scaffolding — monorepo structure #3...) with medal icons for top 3
  • Gamertag + platform icon
  • Selected stat value (highlighted)
  • Delta from [Infra] Terraform: GitHub repository configuration #1 (e.g., "-0.3 K/D from leader")
• Sortable: Click column headers to re-sort
• Visual flair: Gold/silver/bronze styling for positions 1-3

Gamification

• "Squad MVP" badge for the member who leads the most categories
• Stat comparison sparklines showing each member's relative position

Component

SquadLeaderboard/
├── LeaderboardTable.vue     // Ranked table with stat selector
├── LeaderboardRow.vue       // Individual member row
└── MvpBadge.vue             // Squad MVP indicator

Acceptance Criteria

• Leaderboard ranks members by selected stat
• Stat selector changes ranking dynamically
• Top 3 positions have medal/visual treatment
• Delta from leader shown per member
• MVP badge awarded to member leading most categories