The distributed rate limiter (checkRateLimitDistributed) was causing
timeouts in production, likely due to @vercel/kv connection issues.
Switch to sync in-memory rate limiter (checkRateLimit) which works
reliably across all other endpoints.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
