Feat/redis rate limiter

[AugistineCreates]

Closes #212

This PR migrates the process-local Map rate limiter inside createRateLimiter middleware to a Redis Sorted Set (ZSET) sliding-window rate limiter, allowing the backend to scale across multiple replicas, share state, and maintain limits through process restarts.

Changes

1. Redis Sliding Window Middleware: Implemented sliding-window logic using a Redis MULTI transaction containing ZREMRANGEBYSCORE, ZADD, ZRANGE (with scores to retrieve the oldest request timestamp for header reset computation), ZCARD, and EXPIRE per unique IP client key.
2. NestJS integration: Passed the NestJS container's configured RedisService to the middleware factory in both main.ts and security.e2e-spec.ts.
3. Robust Mocking:
   • Mapped @prisma/client to a lightweight proxy mock during test compilation to support local offline runs without requiring connections to external Prisma engine binaries.
   • Refactored the test suite to bypass bootstrapping the heavy AppModule context (with BullMQ workers/queues, database pools, and scheduler jobs), solving local open handles and thread hangs.
4. E2E Testing:
   • Added E2E tests validating that 100 hits in 1 second result in 80+ requests returning 429 Too Many Requests along with the correct rate-limiting headers.
   • Added a fail-open verification test ensuring that when Redis goes down, the middleware issues a warning log and permits requests to flow through instead of returning a 500 Internal Server Error.

[kilodesodiq-arch]

Hi 👋 Appreciate this PR! The CI is flagging a failing check — could you take a peek at the failed job and push a fix? Happy to help if you need a hand 🙏