Implement rate limiting for public endpoints

We need to implement rate limiting on all /api/v1/public/* endpoints to prevent abuse and ensure service stability.

Requirements:

• Limit: 100 requests per minute per IP.
• Return HTTP 429 Too Many Requests when the limit is exceeded.
• Include X-RateLimit-Limit and X-RateLimit-Remaining headers in the response.
• Use Redis for distributed counter storage.

Please refer to the architecture doc for the Redis connection details.