chore(260618-smr): remove redis service from compose files

- docker-compose.yml: delete redis service block (redis:7-alpine)
- docker-compose.dev.yml: delete redis ports override block (6379:6379)

docker-compose.dev.yml

@@ -23,7 +23,3 @@ services:
   mariadb:
     ports:
       - '3306:3306'
-
-  redis:
-    ports:
-      - '6379:6379'

docker-compose.yml

@@ -50,9 +50,5 @@ services:
       timeout: 5s
       retries: 5
 
-  redis:
-    image: redis:7-alpine
-    # Phase 1: present but unused; Phase 4 wires pub/sub for live list sync
-
 volumes:
   mariadb_data: