chore: improve development startup reliability

docker-compose.yml

@@ -2,7 +2,6 @@ services:
   db:
     # postgres database
     image: postgres:16-alpine
-    container_name: piku_db
     environment:
       POSTGRES_DB: ${DB_NAME}
       POSTGRES_USER: ${DB_USER}
@@ -16,7 +15,6 @@ services:
   mailpit:
     # email testing
     image: axllent/mailpit
-    container_name: piku_mail
     ports:
       - "8025:8025" # Web UI
       - "${EMAIL_PORT}:1025" # SMTP