feat: MLOps eval, A/B testing, DLQ, WebSocket, cold-start fallback

updated frontend and solved bugs

fix: Redis AOF persistence volume, api depends_on kafka healthy

feat: cinematic UI redesign (navy+amber palette, genre gradients, skeleton, collapsible simulate panel)

fix: apache/kafka:3.9.0 + python:3.12-slim+openjdk-21 spark, python healthcheck for api

fix: stub prometheus.yml, grafana dirs, frontend waits for api healthy

feat: docker-compose (KRaft Kafka, Spark local, 9 services) and Makefile