Advanced Rate Limiting and Throttling Service (#187)

Objective

• Implement intelligent rate limiting with tiered limits, user-based quotas, and adaptive throttling.

Changes

• Added sliding window rate limiting service with Redis.
• Implemented middleware for endpoint enforcement.
• Added tiered limits (free vs premium).
• Added IP-based fallback and admin bypass.
• Implemented burst allowance system.
• Added rate limit headers in responses.
• Added quota reset scheduling.
• Added analytics tracking.
• Added Jest tests for all scenarios.

Acceptance Criteria

• ✅ Rate limits enforced per endpoint.
• ✅ Premium users get higher limits.
• ✅ Burst traffic handled gracefully.
• ✅ Clear error messages returned.
• ✅ Analytics track limit hits.
• ✅ Tests verify all scenarios.
  Closes Advanced Rate Limiting and Throttling Service #187