Create server/src/lib/validators.ts with reusable schemas for all API
inputs (auth, fights, bets, payments, tournaments, queue, docs).
Import and use in all route handlers, replacing inline validation.
Add formatZodError helper for user-friendly error messages.
77 test cases in validators.test.ts cover valid, invalid, boundary,
and attack inputs (SQL injection, XSS, prototype pollution).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
