Add contributor leaderboard

Add types, hook, UI components, and integration for leaderboard showing top users with badges

src/lib/queryKeys.ts

@@ -111,5 +111,7 @@ export const queryKeys = {
     growthTrends: (days: number, granularity: string) => ['analytics', 'growth-trends', days, granularity] as const,
     entityComparisons: () => ['analytics', 'entity-comparisons'] as const,
     databaseHealth: () => ['analytics', 'database-health'] as const,
+    contributorLeaderboard: (limit: number, timePeriod: string) =>
+      ['analytics', 'contributor-leaderboard', limit, timePeriod] as const,
   },
 } as const;