feat(infra): add Redis service and client for Phase 0 [FASE-0.1]

Add Redis 7 to Docker Compose with healthcheck and persistence, separate logical DBs for blacklist and cache, singleton redis client helpers, and unit tests with fakeredis.

docker-compose.prod.yml

@@ -80,6 +80,8 @@ services:
       MINIO_BUCKET: ${MINIO_BUCKET:-evidence}
       MINIO_SECURE: ${MINIO_SECURE:-false}
       REDIS_URL: redis://redis:6379/0
+      REDIS_TOKEN_BLACKLIST_DB: ${REDIS_TOKEN_BLACKLIST_DB:-1}
+      REDIS_CACHE_DB: ${REDIS_CACHE_DB:-2}
       CORS_ORIGINS: ${CORS_ORIGINS:-}
       AEGIS_ENV: ${AEGIS_ENV:-production}
       ADMIN_USERNAME: ${ADMIN_USERNAME:-admin}