Implement global rate limiter and refactor auth middleware

- Add global rate limiter utility with configurable limits and cleanup
- Move rate limiting logic to middleware for consistent application
- Update auth routes to use new rate limiter
- Add comprehensive tests for rate limiter functionality
- Update documentation with backend development guidelines and tasks

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Docs/Tasks.md

@@ -1,53 +1,3 @@
-## [CRITICAL] Docker containers lack resource limits
-
-**Where found**
-
-- `Docker/docker-compose.yml` — no `deploy.limits` or `deploy.reservations` sections
-
-**Why this is needed**
-
-Without resource limits, single container can consume all host CPU, memory, disk. "Noisy neighbor" scenario where backend memory leak → uses 100% RAM → OOM kill → host unresponsive.
-
-**Goal**
-
-Set hard and soft resource limits for all containers.
-
-**What to do**
-
-1. Add resource limits to `docker-compose.yml`:
-   ```yaml
-   backend:
-     deploy:
-       limits:
-         cpus: '2'
-         memory: 512M
-       reservations:
-         cpus: '1'
-         memory: 256M
-   ```
-
-2. Document these limits in `Docs/Deployment.md`
-3. For Kubernetes, add equivalent `resources.limits` and `resources.requests`
-
-**Possible traps and issues**
-
-- Limits set too low → OOM kill or throttling
-- Backend may need more memory for large blocklists
-- Test under expected load before finalizing
-- Different environments may need different limits
-
-**Docs changes needed**
-
-- Update `Docker/docker-compose.yml` with `deploy` sections
-- Add section in `Docs/Deployment.md` § Resource Allocation
-
-**Doc references**
-
-- `Docker/docker-compose.yml`
-- `Docs/Deployment.md` (resource allocation)
-
----
-
 ## [CRITICAL] Global rate limiting missing
 
 **Where found**