chore: remove unused CATEGORY_COUNT from seed data

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jonasnobile

scripts/seed/generate-data.ts

@@ -131,7 +131,6 @@ export interface Review {
 
 const AUTHOR_COUNT = 60
 const PUBLISHER_COUNT = 25
-const CATEGORY_COUNT = 15
 const BOOK_COUNT = 500
 const CUSTOMER_COUNT = 1000
 const ORDER_COUNT = 3000