Security: Implement rate limiting for user creation endpoint

[coderabbitai]

Overview

Currently, the user creation endpoint lacks rate limiting protection, which could make it vulnerable to abuse through automated registration attempts.

Security Impact

Without rate limiting:

• The API could be flooded with registration requests
• Server resources could be exhausted
• Database could be filled with spam accounts

Suggested Solutions

1. Implement rate limiting using Next.js middleware
2. Use packages like @upstash/ratelimit with Redis for distributed rate limiting
3. Consider using @clerk/nextjs which provides built-in rate limiting
4. Add IP-based rate limiting to prevent registration abuse

Implementation Notes

• Rate limits should be applied per IP address
• Consider appropriate time windows and request limits
• Implement proper error responses when rate limit is exceeded
• Add logging for rate limit violations

Related Links

• PR Discussion: chore: all new changes to session handle, auth, verify user and styling #119 (comment)

Additional Context

This issue was created based on a security review of the user registration endpoint.