Fix storage permissions: use named volume to avoid bind mount chown errors

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

docker-compose.yml

@@ -9,6 +9,7 @@ services:
     restart: always
     volumes:
       - ./:/var/www
+      - storage_data:/var/www/storage
     depends_on:
       - db
   web:
@@ -17,6 +18,7 @@ services:
     restart: always
     volumes:
       - ./:/var/www
+      - storage_data:/var/www/storage
       - ./_docker/nginx/conf.d:/etc/nginx/conf.d
     ports:
       - "8005:80"
@@ -37,3 +39,4 @@ services:
 
 volumes:
   postgres_data:
+  storage_data: