fix: remove unnecessary host port mappings from dev database containers

Postgres and Redis only need to be reachable via the internal Docker
network (portfolio_dev). Removing host port bindings prevents conflicts
with production or other services and reduces attack surface.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker-compose.dev.minimal.yml

@@ -3,8 +3,6 @@ services:
   postgres:
     image: postgres:16-alpine
     container_name: portfolio_postgres_dev
-    ports:
-      - "5433:5432"
     environment:
       POSTGRES_DB: portfolio_dev
       POSTGRES_USER: portfolio_user
@@ -26,8 +24,6 @@ services:
   redis:
     image: redis:7-alpine
     container_name: portfolio_redis_dev
-    ports:
-      - "6380:6379"
     volumes:
       - redis_dev_data:/data
     networks: