Add HealthModule with /health (liveness) and /ready (readiness) probes.
Readiness checks DB (Prisma) and Redis connectivity.
Replaces the basic /health endpoint in AppController.
Co-Authored-By: Paperclip <noreply@paperclip.ing>
Separate root route from health check endpoint. The /health endpoint
now returns timestamp for monitoring integration.
Co-Authored-By: Paperclip <noreply@paperclip.ing>